FPse is the emulator to go for, constant upgrades and its able to use openGL, I have an asus Transformer which I now use as a mini playstation as it has a 10" screen for easy portable use, 2xusb and HDMI.
All depends what your into game wise, it could be anything from spyro, to crash, to ape escape, to metal gear, to resident evil, to tomb raider, to dino crisis, to final fantasy...
