Good news everyone! We exposed a couple of new WebAPIs today, to replace the community ?xml=1 APIs. They are:
GetOwnedApps - to get a list of all games a user owns. (UPDATE: sorry this one isn't ready yet, it will be out next week)
GetRecentlyPlayedGames - to get a list of games a player has played in the last two weeks.

Let me know what you think.