WoW is obviously the big PC gaming point. You can't play WoW on a console right now, even if it was ported. A port would be simply attrocious till they decide to start porting games you can use a keyboard with as a controller.
Strategy games and simulations are the real keys to PC gaming longevity though as well... MMORPG's are the flagship, but you simply can't play a good strategy or simulator on an X-Box. Not yet anyway. That controller doesn't replace a flight stick that has 90 buttons just on it, and the keyboard with another plethora.
X-Wing, TIE Fighter, X-Wing: Alliance... These don't work on consoles. LA tried with Rogue Squadron, and it's ok for what it is, but it's not a flight simulator like the X-Wing/TIE Fighter series tried to be (as much as you can simulate a fictional universe and ships that sorta defy physics). The same applies to flight sims for various warbirds though too.
FPS's I see the argument for both... Mouse/Keyboard though is unmatched in terms of speed and reflexive actions, so to me the M/K and PC FPS's takes the cake for "realism". I haven't played one in ages though, ironically. I play them pretty well exclusively on the 360 now, but if i had a new PC I'd be interested. I always liked the Star Wars ones though and LA isn't interested in trying their hand at one anymore. It's sad because at one point Lucasarts used to be a revolutionary company in the gaming world. Dark Forces took the FPS to a whole new level, and was great EU material to boot.
Then Jedi Knight and Mysteries of the Sith came out, and JK was modded for years and years (another good point about the modding community... There's people still playing games from the late 1990's because they're able to be modded to look fantastic even today). I played some of my best gaming experiences in my life in Jedi Knight, and on modded levels to boot! The one guy crossed Aliens with Star Wars, put a great story to it, and made it a super long playable level in Jedi Knight complete with cut scenes and everything. It was miles beyond a lot of games I've payed to play.
RTStrategy though, is equally tough to put onto a console. You're working practically the entire keyboard, plus the mouse, to manage the true large scale RTS's out there. From old Medeival games I used to love, to Age of Empires, to the Star Wars games that all had charms and flaws... Then Empire At War. I couldn't even fathom how you could consider attempting a port of a game like EAW onto a console. I had a hell of a time keeping everything wrangled with the keyboard and mouse on that one when I played it.
I think from LA's standpoint, they're trying to get on the Console bandwagon, but they're walking away from a legacy of great PC games that you simply cannot duplicate on consoles.
And I'm a diehard XB360 guy, so don't get me wrong here. I adore my 360, I buy a new console whenever the big 3 start putting out new ones (usually MS), but realistically I think PC's always will have a gaming home, and PC's will always be the superior platform if you're willing to stay atop technology to play.
If there were more PC games out I'm interested in, I'd probably be more inclined to drop more into upgrades, but I like to stick to SW gaming a lot on my PC to justify the cost, and they really haven't delivered much I'm into in the past several years I guess. So I stick with my console for now... The Old Republic could really sway me though. Galaxies didn't wrap me up in the hype, but TOR may very well do it.