Supreme Commander is better than Universe at War or World in Conflict.  If I had to order those 3 it would be SupCom > WiC > UaW.  Universe at War is well-balanced, but man the plot and dialogue are awful, and the civs are particularly inspired.  

Other than that, between CoD4 and The Orange Box it's a matter of which you prefer.  CoD4 has one of the best online multiplayers... ever.  It's singleplayer is really short though.  The Orange Box is an incredible collection of games, and of course has Portal, which is amazing.  The Orange Box is the better value, but there is something about CoD4's multiplayer that's just so addictive.  

Oh, and as far as games to look forward to, don't forget Left 4 Dead from Valve. 

my combo is also wii and pc, as they pretty much give me enough of every genre i'm interested in

If you're looking for a good strategy game, get Company of Heroes (if you don't already have it)

between cod4 and orange box, I'd go with OB unless you've already played Half life 2, in which case, call of duty 4 would be an easy choice.

I like UaW because of its free play features. I don't like campaigns, I like playing on LAN. Yes, I did forget supreme commander.

TF2 is why I want Orange Box (but I also want to play Ep.2 and Portal). I love the dynamics of TF2, simple and elegant.

COD4 is awesome.

I am not sure about Left 4 Dead yet. Playing the soldiers sounds like fun but I am not sure if it would have lasting value. I have no interest in playing as a zombie, but if I got the game I would give it a shot.

Left 4 Dead is run by an AI director, and the Zombie AI is completely dynamic (excpet the player-controlled bosses). In other words: A level will never be the same twice. Detailed impressions here http://www.csnation.net/articles.php/article_241/

Oh, and CoH is very good, but it's also WW2. I really can't stand WW2, and I haven't played CoH more than about 10 hours because of that.

The Orange Box is a great game pack to pick up but if you need recommendations here are mine:

-Bioshock (SO much easier to play than with a controller)
-Warcraft 3 and The Frozen Throne (Amazing RTS games)
-World of Warcraft (I didn't like it much but it's still an amazing RPG as far as RPGs go)
-Unreal Tournament 2004 (by far the most refined and overall perfect online MP FPS you can pick up, don't listen to all the COD4,BF, CS junkies :))
-Civilization 4

With those simple 5 games you more or less cover the major areas in PC gaming quite well.

Just to clear this up. I am not totally new to PC gaming, I've played for a long time.
Now I have one that can play newer games.

I already played MMOs: EQI and II, FFXI, SWGalaxies, WoW, some free ones.

I got Half-Life, the day it was available (This was the last FPS I played on PC)

I was playing Duke Nukem, Doom, and Marathon when they were new.

Star Craft and War Craft, check.

I have played all 4 Civ games. Also Masters of Orion 2.

I had an Amiga 500 for god's sake.

I have many, many hours clocked in on RTS games. Age of Mythologies and Dawn of War are my current favorites, but I also play Rise of Nations/Legends and Age of Empires.

I play mostly single player, practicing for LAN parties.

Buy Supreme Commander!

Getting 8 guys throwing up to 1000 units at each other over 80km of land, in edition to nukes, heavy arty, and all sorts of other crazy super weapons = epic win!

I've been a Nintendo/PC/PS2 guy since last gen and finding Starcraft, then really got into Starwars battlefront on the PC, now I'm on WoW and waiting on Starcraft 2, it'll be like the old days where I played Smash Brothers during the day to relax from school then at night fire up Starcraft for some good strategy gaming, except now with Brawl and SC2 ^_^.