I am a loyal Gowalla user in Egypt and they are sending me a package of swag for being so! But I think it is still missing couple of vital features to rock more:

• Check-in comments, so people can ask others about their experience on the spot live.
• Photo uploads at spot.
• Ability to search for a place by text through app.
• Ability to modify (or request to modify) spot location or data through app, as many spots are misplaced due to GPS not working indoors.
• Ability to remove friends from app.
• Ability to create trips through app.
• Ability to view all friends list, not just the ones who recently checked-in.
• Adding ratings, reviews and/or comments for the spot.

Update: Gowalla 2.0 is released on Mar 11, 2010 with photos and check-in comments, nice work Gowalla team :)