The Assassin's Creed series is pretty good. The first game's adequate but slow and repetitive, the second is the series' zenith and the third game is basically more of the second, so get them while they're still decent. I think you can download the first game on the PlayStation Network for maybe $50.
The Prince of Persia PS2 trilogy is, as stated by Yahtzee, the best trilogy of the last console generation. I don't blame him, because I very much agree. It's been remastered for the PS3, so I highly recommend it.
The same has also happened to the Sly Cooper trilogy, which is reliably fun, but I would get it if you didn't have much else to play.
You're a fan of Bayonetta, Devil May Cry and Heavenly Sword, so the remastered PS3 edition of the first and second God of War games should be right up your alley. However, I do feel that the first is significantly better than the second. I don't know if you should bother with the third game. The collection can be bought on the PSN, too.
3D Dot Game Heroes is a delightfully humorous and nostalgic game, and I highly recommend it if only for the humour. Sure, strip that away and it's basically The Legend of Zelda in HD graphics, but the absurdity of it sells it well.
I suggest you take further advantage of the PSN beyond just getting the Gigawatt Blades for inFAMOUS and get yourself Braid. It's fun and simple and rather clever.
Next year, they're releasing a remastered edition of Ico and Shadow of the Colossus on one Blu-ray disc for the PS3. Make room for that.