I was in the same boat with most of you on Halo about the controller, but I'm through 8/10 of the game, and I'll simply say this: Halo is worth the X-Box. It takes a while before you notice a lot of the graphical detail and gameplay nuances if they aren't pointed out to you. I will say, and you might not think this isn't a powerful statement, but I consider that it is considering that I'm a pretty damn seasoned FPS player (w/ a fast computer, Radeon), and now I don't mind playing this with the controller at all. In fact, even though this is the first FPS I was ever willing to play on a console, I look forward to console exclusive FPS' in the future to play on my X-Box. This actually applies to just single player. For a online frag fest, I'd still side with PC's anyday of the week. Sure I can't have my super quick reflexes like in Q3, but this truly feels like "combat evolved." While I like Half Life, this is better without a doubt. But then again, this was made after it, and was able to learn from it like other games.
If you come into the mindset of "this is gonna suck," you're not gonna like it, simply because you won't want to. If you go into the mindset, "Well, lot of people like it, there must be something about it," then I GUARANTEE you'll be impressed. I'm not talking about playing for 1/2 hr at the store. You need to play it at home without any distractions, just like you would with a PC game for at least 2-3 hrs.
I consider Deus Ex the best PC fps ever, btw.
I was just as anal and boo! console FPS as you were, if not more, but I gave it a chance and I'm glad I did.