Handheld emulation alternatives?

The PSP is turning into a bit of a headache for me...
There is a constant war between being able to play the most recent games (and being forced to upgrade the firmware) and being able to support homebrew. I know of the GTA exploit, allowing 2.6 users to run homebrew... but I don't know how well it works, and I'm not sure it's worth the risk upgrading the firmware to play the most recent games being that I've held out with a 1.5 since the PSP's release.
What other systems are good for emulation? I know of the Zodiac, Ngage, Gamepark, etc, but does anyone here own one of those systems and use it for emulation? I'm primarily interested in NES emulation and Gameboy / GBC - nothing too intensive.

You can play homebrew on the DS :)

The GP32 is the second best choice for NES and GB emulation besides the PSP (and it supports many other (b-bit) systems and full MegaDrive/Genesis as well).
I also have a GP2X, but this console really dissaponts me, mostly because of the super-crappy stick.

cool... I'll have to see if I can find a cheap place to pick up the GP32 BLU...