Hmm, well for starters, I'd remove Battlefield Bad Company 2, not because I don't like it, but because for the price of it, you could pick up Uncharted and Rachet & Clank: Tools of Destruction, which, to be honest, will give you more value for your money in terms of singleplayer, although neither of these two have multiplayer.
For the "next gen" Ratchet games, you don't need to have played the older ones really, since they're part of the Ratchet and Clank Future series (Tools of Destruction, Quest for Booty, A Crack in Time), heck, you could even get Quest for Booty too since it's really cheap (It's only a 4-5 hour game anyway).
I'd agree with LittleBigPlanet, especially the GOTY edition since you get some nice DLC with it.
As for Valkyria Chronicles, it depends really, I mean, personally, I loved it, but it's a Strategy RPG, which throws some people off, just think of Advance Wars, but in 3D and you have more control over your characters.
Either way, hope you have fun with your new PS3!







