Look, if you are looking for a multimedia device that does lots of formats and does it well, definitely go for the Archos. Review here:
http://www.osnews.com/story/18948/Th...sed_Archos_604
If you are looking for an internet tablet with SOME multimedia support, go for the N8x0.
If you are looking for a good music player and an ok h.264 player and a so-so internet experience (albeit with third party application support on the way), go for the iPod Touch.
If you are looking for a gaming device with an ok h.264 player, good screen and some basic internet, go for the Sony PSP.

Nothing more to add here, I've tried all four products (own them all) and that's my conclusion. Depends on your needs, what you need the most. No device does everything perfectly.