The GPX2 is DEFINITELY on my must by list. They just upped the memory size to 64MB, so hopeully it will be able to play some Neo Geo.
Since Gamepark Holdings (the company who will release it) is putting emulators front and center as a selling point, and since the specs are confined to fast 2d gaming (with an emphasis on the 2d graphic coprocessor which should up the horsepower of the 2d ability quite a bit over the original GP32), I'm hoping that GBA emulation and butter-smooth SNES emulation will be possible.
Imagine: serious emulation gaming on the go with no DRM concerns, no mod chips or other hacks, no buying overpriced flash memory cartridges, etc. Just buy an off-the-shelf SD card, copy over your emulators, MP3s and games and go! Plus there will be complete access to the SDK library so emulator authors will rejoice.
Easily worth the $180-$200 it will take to get one into my hands.