cant think of anything thats not already on there

PGR 4, Exit and E4 should be on that list. Great thread by the way.

Is this list being continually updated? To echo agabara, I definitely think you should add Burnout: Revenge.

Geometry Wars - 400 points... non-stop fun
Crackdown - 29.99... if you like GTA.. buy this game
Dead Rising - 29.99.. if you like zombie games... this is a must buy
Viva Pinata - 19.99 a family game that deliver hours and hours of fun... so underrated
Kameo - 9.99 .. if you liked old RARE games like Banjo and Conker.. you owe to check this one out

For the under $40 games...
I'd have to say...

1. Condemned - A MUST BUY! No excuses or reasons for NOT having this game if you have a 360. The shopping mall level will give you nightmares.

2. The Outfit - Not a GREAT game, but for $20 I thought it was very addictive and fun, even though its totally not a realistic WWII war game. I like how you can "order" a tank and it is sky dropped right to your location, you can hop in blow up some germans and if your tank blows up, you can skydrop another one, or a jeep, or some soldiers to back you up, etc... The pacing and the moving forward adventure is pretty cool. It's like you meet defenses and forces throughout the game and you slowly push forward with your own. You can set up gunners and artillery soldiers that will fight on their own for you. Then you move ahead and try to get through the enemies lines. Push forward, get killed, secure an area, move ahead a little further, capture buildings and depots, hop in a tank and drive it, set defenses again, etc...COOL!

3. Just Cause - Imagine a GTA type of game on a huge map centered in South America and you're trying to overthrow a corrupt government (VIVA LA REVOLUTION!). You can (or course) run and walk around, but you can also drive cars, trucks, motorcyles, four wheelers, fishing boats, speed boats, helecopters, airplanes, and much more... It's awesome! Plus you have a built in parachute, so you fly a plane and eject before crashing, parachute down, jump in a truck ramp it off a mountain and parachute down, etc... The action and pacing in this game is CRAZY. This game has a hyperactive feel, and the crazy salsa/latin music gives it that Santana-gone-wild feel.

4. Dead Rising - For horror/zombie fans or action/adventure fans in general, this game is AWESOME!
The mall is so huge and there is so much variety and so many things to do.
The photographer aspect is so innovative and really helps to create a totally different game experience.
There are SO many ways to kill the zombies its crazy...
I mean come on swords, guns, baseball bats, chainsaws, cars, motorcycles, lead pipes, teddy bears, soda cans, electric and acoustic guitars, a lawn mower, a bench, an unlockable tank...
There have to be like...a thousand ways to kill these zombies...AWESOME!

Beautiful Katamari. It's addictive as heck.

Might put BK up there once I can confirm it's reached below $40.

Just Cause would be a great one to put on the list (since it's $24.99 or so), but the game, atleast for me, was buggy as anything I've ever played.

I picked mine up at Best Buy for $39.99.  Does that count as "below $40"?  

Yes it does. crumas.

Definetly Condemned and Dead Rising because they are probably two of my favorites on the console.

Some people like to complain about Dead Rising with one save and all. This is only because they do not know how to play the game. I was skeptical about it at first, but then I learned how to play it. Now I play it all the time.

I would go with Call of Duty 4 if you want Multiplayer. There is a good single player game too. However, multiplayer is definetly the best FPS multiplayer to date. I feel that it completely buries Halo 3 in almost every way.