If gaming is the priority you should absolutely get the Dell 8600 which has the ATI 9700 video card with the 128mb dedicated video option. You can get this ATI video card on the hpzd7000 for example (see zd7000forums.com -- 9 pounds 17" LCD Pentium 4M) if you want a desktop replacement. The Dell 8600 will give you better battery life though and less weight (6.9 pounds). The only negatives of the Dell are the case integrity (nearly all plastic) and the keyboard is not as good as IBM, the HPZT3000/Compaq X1000 series, etc.

But the Dell 8600 is one of the only mainstream Pentium M notebooks (15.4" widescreen) with the Hitachi 7200rpm hard drive and 128mb dedicated video as options at ordering.

I am not aware of any mainstream Athlon 64 yet that has 128mb dedicated video (HP/Compaq or Gateway/E-machines -- they all top out at 64mb dedicated and that is not enough for full settings if you play games alot).

I would get the Dell in a hearbeat over fringe companies like the Sager or Alienware for the service issue under warranty and especially any parts needs later even if out of warranty.