I actually love the trackpad when I'm just doing general browsing and whatnot on the MBP. The gestures and multi-touch really do make it alot smoother.
I still have a mouse I'll use when I need more accuracy, drafting/plotting, gaming, etc. But for everyday use, I think the trackpad is fine. My main issue with using a mouse constantly is that it chews up one of my USB ports, and as I work on a ship, real estate in my cabin is at a premium, so I really don't want a big powered USB hub taking up space/power plugs just so i can plug in my external HDDs.
But as has constantly been stated, it's all personal preference.