PC is by far my favorite.
It's just so much more streamlined than any console, because I can do whatever I want with it, no restrictions. I'll browse the internet, work on some homework, and chat with friends all at the same time...then in a couple seconds I can launch TF2 and chat while playing.
As for controls, the only thing you could maybe argue against the PC is the keyboard. I have absolutely no problem with it, and I think most people that argue against it just aren't used to playing with it. Which isn't fair, considering you've had nearly a decade of practice with dual analogs. The only "problem" I can think of with the keyboard is the lack of analog control. If you want to slowly step forward, or gradually increase thrust or whatever, there isn't much of an option with keyboards...it'd be nice if gaming keyboards came with a slider for some analog support.
Otherwise a keyboard+mouse is way more accurate than a dual analog controller...and if you really want to use one, it's almost always possible.
So if you say "I don't like PC because using the keyboard sux!" you don't know what you're talking about.
Also, having to upgrade should not be considered a negative...mainly because you don't HAVE to upgrade. If you want to build a rig with PS3/360 level graphics, do it, and you shouldn't have to upgrade again unless you want BETTER graphics. So yes, if you want the best of the best graphics all the time, you'll be upgrading a lot. There is no need to max out every game though...you can get through a whole videogame generation on the same rig if you start with a good one. Or at least, only spend $100-200 on upgrades...hardly expensive.