A couple things here.
1) I am not a big fan of prebuilt computers. Mainly because it used to be that you couldn't build anything comparable for less. That's not entirely true anymore. I have a dell server (sc420) with a 2.4 celery (it was $100 bucks less then a p4) 512 ram and 160gb Sata drive for less then $250. I would love to see someone pull that off cheaper (at pricees 3 months ago). To top it off, it has been up and running (fedora core 3) for the better part of a month with no problems (knocking on serious wood here)
However, my gaming box is built entirely by me. I got a mobo and cpu cheap, found a cheap video card. In fact, the most expensive thing in it is the memory.
I guess it's kinda hard to find non-prebuilt laptops

I got mine from a company called mwave. I haven't had any problems they weren't able to fix right away. I think it's all about luck.
2) Alienware computers (and more on prebuilts). Overpriced computers... the only thing you are paying for anymore is the name. They are the top of the line, or at least very near to it. But there is no way that they should cost that much.
The one thing that you do tend to get out of computers like these is reliability. When someone else puts together a computer and thouroughly tests it (like alienware or dell) you are almost guaranteed that all of its components will play nicely with each other. You don't have that same guarantee with a homebuilt.
3) Macintosh... quite possilby the most debately computers on the market. Sure the hardware/software costs more then you would for an intel box... sure the hardware/software is limited in quantity/quality... but they sure have some good, I mean great points about them.
When it comes to graphical/video design/manipulation nothing beats an experienced user on his/her macintosh. There just exists better software.
But you don't buy a macintosh to be a gaming pc... duh
Enough of my ramblings... personally I kinda like linux. (doom3 runs on it

)
ps if you think installing gentoo is easy, your nuts.

I spent a weekend trying to get it to compile. I learned tons about how my computer works (as well as *nix), but I still didn't have an operating system on my computer by monday.
