Which Audio Interface?, FW or USB 2? Options

[timski]

I am in the process of starting up and wanted some advice on audio interfaces.
I have a 1Ghz G4 Powerbook (2x USB 2 ports, 1x Firewire 400) with Jaguar (may be getting Panther soon, however) and am planning to run Logic Express, recording mostly audio (vocals, guitars and old keyboards) with some MIDI. I do not require surround sound and do not plan to use any extra hardware (MIDI devices, mixers, etc) other than a MIDI controller keyboard.
Do I really need Firewire or is USB sufficient? The M-audio 410 looks nice but I have reservations about the fact that I'd have to keep it switched on all the time as this really isn't feasible - I require portability and use my PB for much more than just music. Furthermore, I may eventually want to record live drums and wasn't sure if the 410 would give me enough inputs.
There are a lot of cheap USB interfaces like the Tascam US-122 and the Audiophile Pre - would one of these be sufficient?
Finally - I will be getting an external HD, preferably Firewire. Can I run this at the same time as a 410, or could I get away with a USB 2 HD?

As I said I'm just starting out (although have some experience with recording using Cubasis and EMU APS on a PC a few years ago) so don't need anything too fancy, but at the same time want gear that will last a long time and won't limit me in the future.

MANY THANKS!

This post has been edited by timski: Thu 6 May 2004, 21:48