Some of the Best Xbox Live Games
3D FPS Multiplayer
Battlefield 1943, 1200, $15
It's battlefield 1943 with up to 24 players. It's one of the top rated games, so you can't go wrong with this one.
Braid, 1200, $15
If you love platforming and games that make you think, then give Braid a try.
Portal Still Alive, 1200, $15
It's Portal; It's awesome.
Side Scroll Adventure--think Metroid
Castlevania: Symphony of the Night, 800, $10
Do you like Castlevania? If you've never played a Castlevania game, then you should start now with this one.
Shadow Complex, 1200, $15
I haven't played this game yet, but it is highly rated and is said to be the Metroid of our time. That was enough to sell me, so I will be buying it.
UNO, 400, $5
It is faithfully UNO with tons of live players to play against online.
Vertical Scrollers (Shooters)
Ikaruga, 800, $10
So, you blast away spaceships, but there is a twist. You can switch your ship from black to white, which allows you to phase through black or white bullets respectively. This gimmick adds a whole level of strategy not found in other games like it. It's one of the best shooters of all time, period.
Wolf of the Battle Field: Commando 3, 800, $10
As I said before, great game.
Biology Battle, 240, $3 (Indie)
Geometry Wars Retro Evolved 2, 800, $10
That is my list of the best live arcade games, of which there are more; though, these should keep you busy for a while.