As far as multimedia machines. Compaq, HP, Toshiba, and anybody else who makes PPCs, suck. Casio makes pretty good devices though. The E-200 (ARM) and E-125 (MIPS), are the only PPCs that I have heard, are worth a damn for multimedia. All PPCs though, have their plusses and minuses, when it comes to it.
If you want more add-ons than you can shake a stick at, then buy a Compaq Ipaq. If you want a gaming device, go with Toshiba or Casio, and if you want a buisness machine, then go with a HP Jornada (Although the new 560 series, is not too bad for gaming either).
The 206MHz ARM processor (currently the fastest RISC processor on the market), and no video card, in all the high end PPCs, make all of them pretty shity.
But, when the 400MHz XScale processor and ATI's PDA video crad hits the market, you will have a very powerfull PPC indeed. Untill, then, bitch, whine, or whatever floats your boat.
