If looking for 2 player local co-op games my vote goes to PixelJunk Monsters hands down. Another game I really like is Bionic Commando Rearmed. This has 2 player local co-op also. I haven't played Burn Zombie Burn! yet and in fact I was thinking about buying it the other day. It got good reviews.
Glad you got Fat Princess and Shatter, which are two of my new favorites. Looks like Fat Princess will have lots of replay value for me, I couldn't stop playing it last night.
If your into shooters SuperStardust HD and Everyday Shooter are a couple more favorites of mine. Battlefield 1943 is also great fun for a small downloadable title although I wish it had more maps and more gameplay modes so it's replay value is low for me.
Or you could save the $17 for a couple of new releases coming soon like Trine (3 player local co-op), TMNT Turtles in Time (4 player local/online), PixelJunk Shooter (2 player local), or Zombie Apocalypse (4 player local/online).
