Leading the pack with 5-star ratings are an iPhone port, an Xbox Indie port, and a bunch of games we've never heard of:
Further down in the 4.5-star ratings are more iPhone ports from both lesser known developers like Celestial Digital Entertainment Limited's Attack from the Dead and old classics like Sudoku. It isn't until you get to the 4-star rated games that you start seeing big publisher titles like Need for Speed: Undercover, Bejeweled, Rocket Riot, and Star Wars Battle for Hoth.
Based on the early days of both the App Store and Android's Market, it'll take a month or so more for the Windows Phone 7 marketplace to shake out into clear hits and misses. Prices might also fluctuate for indie titles, but those big-publisher games are probably stuck at $4.99 and $6.99 thanks to their iPhone/iPad counterparts.
Keep tabs on what you're playing, and send us a line if something seems really cool.