I'm using a ThinkPad R31 as my music machine (and development, and everything
else)
The internal sound card is an Intel 810 which seems generally ok - duplex i/o
works in alsa, not in oss. Only mono microphone in.
I've recently got a m-audio quattro usb soundcard to use with it, for the
multiple i/o and midi.
Generally I really like it, and it's replaced my desktop machine (for
everything except cd burning and PIC asm programming)
I don't use the batteries much, but I have got 3 or so hours out of it under
normal use, maybe longer.
It's pretty small and light - but not too much so, the keyboard is exactly the
same width as a normal desktop one without the keypad, so it's not too hard to
get used to. It feels pretty solid and nothing's fallen off or broken in the 7
months I've had it for. :]
dave