Am I that far out of the intended user base of the 15/17 MBPs??!!?
I thought a lot of people use their 15 as a desktop replacement when they need occasional mobility but are generally using it in a desktop fashion......
It's quite normal. Most companies now operate in this manner, as well. Everyone gets a laptop and a docking station at work.
This way you can move around and do work on the go (ie. bringing it home to work after hours), but have an ergonomic and productive workstation at the office. No need to have two separate computers.