I alreay have xbox and a gamecube so im not biased.
I suggest that you wait after E3. supposedly they are going to have a smaller xbox and also a pricedrop. Youll be beating yourself if you get the big one and then like a month later the little one comes out even cheaper. And yes xbox is worth the purchase. Now if you're into rpgs you might be better off with the PS2. Xbox tends to have action games. And then it aslo has the games wich gamers just LOVE. Gunvalkyrie, enclave, Dead to right, Splinter cell, Panzer dragoon orta, Shenmue, Morrowind, RARE, and it would also give you a bigger library of games. And if you have broadband you HAVE TO get an xbox. Especially with Capcom vs SNK out and Return to castle wolfeintein on the horizon. And halo 2 and true fantasy live ready for this xmas season. And on top of that all the sports games.
And about halo: if you are going to buy the box JUST becuase of this, then dont, but if you wanna go online or there are some interesting games on it then go for it. And no Halo on the PC will NOT support online play. how do i know this, cuz everyone at the the xbox forum would have alredy made 100 threads about that. And no it will NOT be better looking on the PC either. Maybe resolution but thats it. And if you alredy have friends who have halo on the box, then go ahead and get it. Theres nothing that beats a lan party on a friday night with pizza and orange juice( i hate soda) along with all your friends cursing at the top of their lungs cuz you sniped them from all the way across the stage.