[Fathom Zero]

I had shitloads of fun with mine before it got stoled.

The Syphon Filter games make me feel like a spy in a way that Metal Gear Solid was never able to. The multiplayer in it is far better than the Portable Ops games. But I don't know how many people are playing it anymore. All of the games you mentioned are righteous, and you should put Death Jr. and Twisted Metal on your list, as well. Pursuit Force is fun in a very silly way.

And, if you do go the modding route, don't ask me about it because I'm sick of explaining it to little bastards. If you do decide to, it would be the most powerful handheld emulating device on the planet. Until the Pandora comes out.