Good to hear of all the advancements, abf!
Seablade, even though the ATI drivers are binary, the kernel "hooks" must still be recompiled for every new kernel. I don't know the details, but thats what happens. Every time I upgrade my kernel, I have to recompile the ATI drivers, the Synaptics module and NDISWrapper, although I don't use it anymore.
Abf, the Gentoo base-layout includes a very convenient init script for setting up wireless. Basically, when you start your /etc/init.d/net.wlan0 (or whatever), it knows its a wireless device so it calls a special wireless script. It does things like scan the surroundings and figure out your preferred APs. Anyhow, the config is in /etc/conf.d/wireless and an examples is in /etc/init.d/wireless.example. I think there is a HOWTO on
http://gentoo-wiki.com (very good resource). Browse around. Learning how to deal with all this via the console is extremely valuable; use GUI tools for convenience, but you should still be able to do things by hand if need be.
Finally, as for "post-install tweaking", enjoy yourself! I can honestly say that I didn't stop tweaking my Gentoo until at least a year after installing it.