powerule, for most of us here... we are concerned a great deal more with the 17" models than the 15" models. We've been able to, at numerous occasions, get great deals on laptops that we couldn't possibly build a desktop equivilent to for the same price or less.
Yes, we are somewhat consumed with the video cards... but video cards are the one least upgradable piece of equipment in a laptop (other than the screen). This means that is the piece that must keep up with technology the most if we plan to get a long term return on invest in these machines. Make sense? We are more concerned with how long they will be able to serve us in games, applications, operating systems, etc then we are concerned with how long they can stay unplugged.
We want the "whole package". Sure, 2 hours on battery isn't much... but it's more than a desktop can do. Although this 17" feels lighter on my lap than the 15" I use for work... the 17" is indeed heavier. Having either one on your lap longer than 2 hours will eventually lead to blood circulation issues in your thighs anyhow. So no biggie.
We have a 7.5lbs package that we can carry in one hand anywhere we want to go. It's easier to goto lan parties, commute from home/office, and take it on trips then a desktop is.
So in the end... what's wrong with wanting it all? Nothing. And just remember, the one thing holding back laptops the most is how advanced your video card is. Even professional apps benefit from a better video card, it decreases the load on the cpu and produces results quicker in optimized multimedia applications.