I personally prefer using a mouse. I hate touchpads because I have this nervous thing where my hands get really sweaty and ends up screwing it up. I only use the touch pad if I need to be extremely accurate and can't be with the mouse.
As for what makes animating a lot easier? Have a really good computer processor and high RAM, my 3 gigs suffices even though I get a few "Not Responding" times yet it still works. Any mobile processor of 2009 or later seems to suffice enough in CS5.5, so I say if you're around that you're golden for the time being.
I'm only messing with sprites, however, so it could be different for hand-drawn animations and much much longer animations.