I can't seem to find a mouse with pinky buttons anymore
but here's a decent mouse for movement if you can configure it properly (or if the HL Engine supports it, I have NO idea if it'd work)
Intellimouse Explorer
Yes, it's a microsoft mouse...so what? The guy who I know hwo has the mouse loves it...I'm still looking thru mice tho...if I come up with anything else I'll keep people posted ;) and there are wireless versions as well
Microsoft Mice