My Toshiba Qosmio X505-Q892 does what I need it to do. Battery life is around 3.5 hours if I just do basic activities, MS Word, etc, and about 2 hours for gaming if I want to play a little bit. I carry the brick wherever I go regardless.
It's amusing actually. I customized the power settings so that the screen's brightness is lower, the screen goes idle sooner, and automatically downclocks to the lowest clock faster than the power saver feature it comes with. XD So my Performance Mode uses less power at idle and lasts the longest.
I got smart with this machine.