Yay Gentoo! I love my Gentoo
.
But stay away from genkernel.. it kinda defeats the point of having customized everything. If you just take the time to configure your kernel (takes, what, 30 minutes?), and then do "make && make modules_install && make install", your kernel will be MUCH faster. And when you get a new kernel all you have to do is copy the old config over and do a make oldconfig, then you have your old config + all the new options that you want that come with the latest kernel. Takes very little time and it pays off.
Also, I would definitely stay away from ATi if you're going Linux, Gentoo has very good nVidia support and it's best just to stay with them. On my Athlon64 box I have a GeForce 6200TC, it's cheap but pretty good (I can max out my ut2004 settings without a problem). My motherboard is an nVidia nForce4-939; I would also reccomend one of these as it has good support. Stick with Socket939; IIRC the other Athlon64 sockets are being retired in favor of 939, so this way your box will be easier to upgrade in the future. My processor is a homely 3000+ but it is still quite an improvement over 32-bit processors when in 64-bit mode.
Oh and memory - I bought two seperate sticks of 512MB, so I have dual-channel giga memory. Don't fall for buying the more expensive dual-channel memory packages (where they give you two memory sticks all in one package), it's just a waste of money and buying two seperate sticks should work fine. I would say 3GB is mucho overkill, but it's your choice
. I never have memory problems myself with 1GB. What exactly are you going to do with 5GB total memory anyway?
You will definitely notice a significant improvement when using portage/compiling stuff/etc. when using a 64-bit OS. Make SURE that you're doing a Gentoo x86_64 install, if you do regular x86 you'll be using 32-bit emulation and won't notice much of a difference. Although Gentoo64 doesn't have as much support, it's getting there and all kinds of apps are improving their 64-bit compatibility every day, so don't sweat it
.
If you do get an nVidia card, make sure you read the Gentoo handbook page for nVidia (google it) - this is priceless info!
Finally, I reccomend that you subscribe to
Transgaming ($15) and get Cedega if you want to play any Windows games on linux. Setting this up can be a pain, but if you can get things working it'll be worth it.
Okay, that's about it.. I hope I didn't bore you with anything, but instead helped you a bit
EDIT: Oh, don't listen to those crazy FluxBox guys, on Athlon64, KDE runs very smoothly
. That doesn't mean it's simple or anything...