Also, the 3DS will have ports of 64 games,
It has only two remakes (not ports) of Nintendo 64 games right now, and that doesn't mean there are going to be any more. The DS launched with a remake of an N64 game, and it was never followed up with any more. There are a lot of good Nintendo 64 games that will likely never see re-release, so it's a system worth picking up at some point.
Though if it's 2D gaming you're after, then the Super NES is the best choice. My personal three favourites are Earthbound, Chrono Trigger, and Super Mario RPG, though all of them can fetch some high prices. Faceball 2000 is high up on my list as well... though I s'pose that's 3D. Oh well. Hm, I'm sure there are others I liked... it's been a while... The games Maxi mentioned are all good choices.
Personally I feel NES games have aged terribly. They're just so primitive and simple, and often have horrible controls or other technical issues. There are a few that still hold up, but nothing really beyond the staples you already know about, like Mario and Zelda. Oh, I guess Mega Man. That's still fun.