What I like about the PSP is the fact you can load mpeg4's on a memory stick and they look very good. Sort of a moble video player with good resolution. 1/2 the price of the Archos player.
Also, wireless built in, and a web browser is available in the game Wipeout. Already some PSP portals up and running and RSS feeds available.
The UMD disk is rumored to be a Bluray disk, so it will be a while before we have any kind of access to those as far as burning, etc. The size of a minidisc but different format, spindle hole, etc. The games are nice as well. I have Twisted Metal, Lumine, and Wipeout. Nice entertainment.