The external mouse was a good choice. I use my TiBook as a desktop replacement at school, and while the trackpad's fine and all, I think I'd go insane very quickly if i had to use it ALL the time.
I also just ordered myself a D-Link 4 port USB hub because having only two USB ports is kindof a drag when you want to hook up printer, scanner, mouse, digital (still) camera, PDA, and all use USB. It's not exactly the dock you were looking for, I know, but look into it; a hell of a lot of devices use USB, so it's probably worth it. What's more, if you're going to be using your firewire hookup a lot, D-Link also makes a hub with four USB 2.0 and three firewire hookups. Regrettably, it's only firewire 400, but I have a TiBook, 'the hell do I care? (Although even that'll kick the crap out of USB). Anyway, if you want a dock-like device, check out that USB/firewire hub. It's not the same, but hell, it's about $250 cheaper, too.
edit to include this:
as far as speakers go, Cambridge Soundworks makes absolutely phenominal ones. The sound quality's amazing, the speakers, themselves, are simple and attractive, and they're so cheap it almost hurts me. My speakers are years old and still make me proud and were $40. Quality goes up relative to price, too. Guaranteed you'll be happy with them.
and this:
It's true: if you can get an ipod, do it.