Finally beat it. Fifty one and a half hours, 49 poes, all but 2 golden bugs, and all but four heart pieces. Also beat the Cave of Ordeals before beating the game.
I'll denote some parts of the game that I really loved (I won't be able to get all of them, but maybe I'll post more later as I remember them), then ending impressions and problems I had with the game.
Malo Mart once it opens in town. I was expecting to go in to a normal store, and suddenly HAPPY DANCING CONSUMERS and the moonwalking vendor? Awesome. Also more hilarity when I went back to Kakariko and the Goron elders were doing the dance.
The Western-style battle in the Sheikah ghost town, and then the hilarious follow-up minigame with the cats. I love that they derive such enjoyment from just talking to you 
Beating the fifth dungeon (Snowpeak Ruins), with the lovely cut-scene with the Yeti couple. My friend (who was watching) and I cracked up at that. I like the two of them in general, too, and sledding against them is tons of fun.
Also in Snowpeak Ruins, the miniboss! It was the ball and chain knight from Link to the Past and Link's Awakening! Fun battle with total nostalgia, but even cooler when I discovered that I GOT THE BALL AND CHAIN.
The minibosses in general, really. I loved all of them, and the lack of minibosses was, in my opinion, the biggest flaw in Wind Waker.
Getting the spinner and realizing how awesome that boss was gonna be. Really wanted more spinner-centric areas, though. It had morph ball puzzle potential, really. Maybe a cool minigame with it, similar to the sledding thing.
Kind of earlier, but beating the Goron Mines and having it become sort of populated again. Oh, and hitting the pole on top of the lookout tower on the first try, and without the scope. Wiimote ftw.
Iron Knuckles hella yes. While the fighting in this was incredible, and I loved all the combat, I still felt Wind Waker's was more fun. The swordfighting in Wind Waker felt more natural and the items in Wind Waker could be used to better effect in combat than those in TP. I also love constantly toggling with the camera; one of my favorite things in Wind Waker was taking the helmet off of a Darknut while zooming around with the camera. Anyway, both are really great, but Iron Knuckles really stand out in how excellent they are to fight. Most of the enemies in TP felt too easy, I could kill a horde of enemies with one swing of the Master Sword, but Iron Knuckles were really satisfying, and I wish there had been more like them.
Boss battles, needless to say. Armaghoma, the Stalfos Lord, Diababa, and the dragon (whose name slips my mind) all stand out.
My favorite one, though? Zant. I LOVED that battle. Hands down one of my favorite Zelda bosses ever. Both the interesting revisiting of past bosses and his crazy, quirky behavior. Zant was such a cool enemy.
Also, all the minigames. And I've really enjoyed fishing a lot more than I thought I would. Hena is adorable (I said she was cuter in that picture).And now ending stuff:
Interesting. It felt kind of abrupt, especially considering how long the game is. Also, as Bill noted, absolutely no connection to what happens prior to Wind Waker, which I would have liked.
Fighting Ganondorf was great, all four stages were awesome. I died on the Ganon stage, took me forever to get Midna's grip right (I was diving forward instead of waiting), but I beat it after that. Horseback awesomeness and quite a good finale. I absolutely loved the shot of the sun setting with the silhouettes of Zelda and Link looking at Ganon, standing (in some sense at least) lifeless.
Also, I think the Zant cut-away had something to do with what he said about his god resurrecting him. When Ganondorf lost his power, Zant died for good.
Midna is quite beautiful, yeah. Love the art on the first page of the instruction manual, but glad I didn't see it till after I beat the game.
Every Zelda game seems to have some tragic quality to it. Midna leaving and breaking the bond between the two worlds. That scene was beautifully done. It felt, well, tragic.
Credits stuff was good, of course, and Link riding home. I like Ilia, though I wouldn't be able to decide between her and Midna. She looks a bit odd, but I still like it. Hena is cutest, though. I hope we see another game with this Link.
Going to beat it again soon, of course, and I'll watch the ending again. But that's what I have to say for now.Problems:
My biggest gripe is the story. And not the story itself, which I like well enough, but how it's told. It's told almost exclusively in cut-scenes, and almost entirely: after the first three dungeons, after the fourth dungeon, and after the seventh and eighth dungeons. There are severe story draughts. Whereas some games succeeded very well in continually telling the story (Wind Waker, Majora's Mask, and Link's Awakening), Twilight Princess (and OoT and LttP suffered from this too) felt too disconnected, in terms of how the story advanced.
On the other hand, I'm partially to blame. I played the first dungeon, didn't play at all for a week, played the next two and then waited another two weeks before I started playing again (and then it took me about a week to finish the game).
I'm going to play through again sometime, but as of now this still seems a problem to me.
I also feel like there weren't enough characters. We had a few memorable characters, most of whom played an important role, but aside from characters like Agitha, Jovani, the mailman, the two clowns at Hyrule Lake (all of whom serve some distinct purpose) there weren't any memorable characters. Castle Town was great, with all the hustle and bustle, but unlike Ocarina's Kakariko Village or Wind Waker's Windfall, very few characters had any importance. I'd like to see a more diverse cast of individuals (although I may point out that the individuals who are in the game are awesome), and have Link help certain characters in some way. Not enough dynamic characters.
Also, in conjunction with this problem, there are certain areas that I didn't feel connected with, because they didn't make those areas involved as they could have been. Ordon was fine at first, but after you leave there's virtually no reason to go back there, unless you want to just hang out or herd goats. The Goron place in OoT felt very special, because there was a lot to do there. Here, all you had to do there was wrestle and beat the second dungeon. All you do in the Zora Domain is unfreeze everything, and later use it as a bypass to Snowpeak. These areas are brilliantly designed (and Zora Domain is visually gorgeous), but they're relatively empty.
Anyway, the game was still absolutely brilliant. The art design, every single inch, was spectacular. The environments were beautiful. The characters were great. The enemies were fun to fight, and the bosses were awesome. The music was beautiful (especially at night, on the field). I could go on and on about why I loved the game. It's one of the best games I've ever played.
But it's not my favorite Zelda, and I don't know that it would even surpass Wind Waker.Now after that huge post, a questions and such:
Reading through this thread, I'm quite proud of myself. I made it through every dungeon with relative ease (I only really felt challenged in
Hyrule Castle, and then only occasionally), without any help whatsoever. I collected nearly everything without help
(after I beat the game, lacking only four heart pieces, I continued to collect them: I now have all of them. I used the fortune teller four times: once to find out what she did (she showed me the donations guy, so at the time I didn't realize what it meant), once to see a heart I already knew about, and twice to actually find two I had missed (in dungeons).
I only need ten more poes.
I beat the Cave of Ordeals without any outside help. I had to go through twice, because I didn't have the item I needed to continue the first time. I did not die when I played all the way through, though it was a challenge.
I'm missing only two bugs. This is the only problem I have right now. I'm missing a pair, and I don't know where to find them. I've looked everywhere. It's the top of the middle column (on the bug menu), so if somebody could give me a hint, that'd be great. No specific locations, though, thanks.I'll say more later, if I have anything to say. Sorry for making such a MASSIVE POST, hope someone is willing to read through it
EDIT: SixthAngel and I are looking for the same bugs.