XBOX LIVE ARCADE (360)

The purchasing system is stupid and irritating ($1.25 = 100 Microsoft points? WTF?), but the selection is absolutely enormous. Over 100 titles cover almost every genre and era.

In picking the winners, we've tried to avoid the obvious. (See our choices above the big screen.) Even your grandmother knows that stuff like Doom, Castlevania and Geometry Wars are good. The losers, however, are often very well disguised. (See them below the big screen.)

DOWNLOAD IMMEDIATELY!

Undertow ($10) - Imagine the simple fun and beauty of Geometry Wars. Now plunge that dual-stick shooter underwater, replacing neon space polygons with submarines, harpoons and Atlantian soldiers. Then add layer upon layer of strategy, teamwork and, best of all, multiplayer to make Undertow the bargain bin prize of the year.

Carcassonne ($10) - Why waste the power of your Xbox 360 on an adaptation of a board game designed by a German music teacher? Because you probably haven't had this much fun claiming territories, building kingdoms and trash talking friends since you first learned how to play Risk. Plus, no pieces to pick up at the end!

Switchball ($10) - Not to be confused with the mediocre Speedball 2 or the terrible Cyberball 2072, this peaceful puzzler asks you to guide a shiny marble through challenging landscapes filled with ingenious traps and devious obstacles. Your brain might strain, but the music, graphics and overall pace are surprisingly relaxing.

Puzzle Quest: Challenge of the Warlords ($15) - The most addictive game released this year, Puzzle Quest is basically Bejeweled with a story, monsters and multiplayer tossed into the mix. You won't entirely understand why, but you will play this for months and months to come.

Psychonauts ($15) - Microsoft recently introduced a new section to their online network - Xbox Originals. Here, you can download and enjoy full versions of popular products from the last generation of gaming. Psychonauts is not only the most overlooked of the first offering, it's also the best. Yes, better than Halo.

DO NOT DOWNLOAD!

Cyberball 2072 ($5) - Everything that was fun about this arcade favorite has been stripped out. You probably remember playing against three of your friends; now, you can only compete against the computer, who happens to be very, very dumb. Sure, a buddy can join your team, but that will just make the game even easier and its replay value even shorter.

Scramble ($5) - Xbox Live Arcade includes a ton of retro space shooters, some holding up better over time than others. If you're craving a dose of hardcore, thumb-blistering nostalgia, we recommend trying Time Pilot, Galaga, Asteroids or Defender before giving Scramble a shot. The aging process has not been kind.

Space Giraffe ($5) - Do you know and adore game designer Jeff Minter? No? Then avoid this indecipherable acid trip at all costs. We know the title is cute and intriguing... just trust us. If you do know about Jeff Minter, then why are you listening to us? Didn't you already download this a long time ago?

Pac-Man / Ms. Pac-Man ($5 each) - Tread carefully, as three different editions of the iconic yellow chomper exist on Arcade. The one you want is Championship Edition, which actually updates the classic for modern audiences with fancy new graphics and modes. Pac-Man and Ms. Pac-Man, surefire as they sound, suffer from poor controls.

Screwjumper! ($10) - Despite the prominent exclamation mark, Screwjumper! is far from exciting. In fact, considering all you do in the game is jump down a hole and try to hit green objects while dodging red objects, it's rather dull. Throw in shoddy controls, plus a ridiculously mismatched price tag, and what you get is just plain insulting.