The Xbox Live Arcade Awards for 2008 will be accepting votes from March 3 at 10:00 A.M. GMT, and ends Tuesday, March 10 at 11:59 P.M. GMT so get your votes in now if you'd lke to see an arcade favourite of yours get recognition.  There are 9 categories and the final winner for each one will be decided with votes from the Arcade Awards Voting Application downloadable from the Xbox Live Game Marketplace.  All games can be viewed in screenshots or downloaded directly from links within the Voting application if you'd like to check them all out first hand before you vote.  Votes can be downloaded at any time before the deadline.
More details, and the winners once they're announced, can be viewed here: http://www.xbox.com/en-US/community/events/xblaawards/.
I'll be the first to admit I'm not particularly well versed in arcade game downloads from xbox live (though i did have a browse through some of the original xbox games available and will be downloading a movie with some free points I got) but I really like the fact that these kind of votes are happening.  Hopefully the voting application will be put to more uses in the as it is with the wii voting channel.
 
Best Family Game

• Boogie Bunnies
• Roogoo
• A Kingdom for Keflings
• Lost Cities
• Meteos Wars

Best Original Game

• Castle Crashers
• N+
• Braid
• Penny Arcade Episode 1
• Schizoid
• Age of Booty

Best Classic/Remake Game

• Bionic Commando Rearmed
• Street Fighter II HD Remix
• Mega Man 9
• Galaga Legions
• Rez HD

Best Overall Arcade Game

• Braid
• Castle Crashers
• Geometry Wars Retro Evolved 2
• Street Fighter II HD Remix
• Portal: Still Alive

Best Co-operative Multiplayer Game

• Castle Crashers
• Schizoid
• Bionic Commando Rearmed
• N+
• Geometry Wars Retro Evolved 2

Best Competitive Multiplayer Game

• Street Fighter II HD Remix
• Geometry Wars Retro Evolved 2
• Soul Calibur
• Meteos Wars
• Age of Booty

Best Solo Game

• Braid
• Mega Man 9
• Penny Arcade Episode 1
• Rez HD
• Portal: Still Alive

Best Innovation in XBLA

• Braid (time travel)
• A Kingdom for Keflings (use of Avatars)
• Fable II Pub Games (retail game integration)
• N+ (level sharing)
• Duke Nukem 3D (dynamic replay)

Best Graphics

• Street Fighter II HD Remix
• Geometry Wars Retro Evolved 2
• Braid
• Castle Crashers
• Bionic Commando Rearmed