I was just browsing this thread for kicks, but I thought I'd throw something in there:

DOUBLEJOON:

Make sure you are *appending* to your make.conf with the '>>' as opposed to the single '>'. If you follow the command exactly in the handbook, it shouldn't bork it at all. I have seen, however, that mirrorselect does not always select the fastest mirror. The fastest mirror for me was not detected as the fastest and often all four that mirroselect picks (with the switches in the handbook) are definitely not the fastest, so, as they say, your mileage may vary.

My Gentoo compile experiences:

1st-
AMD Athlon64 3200+
1 GB RAM
Stage 1
Took Friday night from 7 pm to about midnight, then I went to sleep.
Woke up Saturday, continued with emerge system, and by the afternoon, could start merging to build the desktop

2nd-
Intel PIII 850
256 MB RAM
Stage 1
(Laptop)
Started bootstrap to run overnight, it finished sometime in the wee hours.
Emerge system, found that the mirror reference in two ebuilds was wrong, fixed that, then was ready to build the desktop by that evening.

Regarding compiling Firefox from source:
It doesn't take half a day. A lot of it depends on your use flags that Firefox will accept. IIRC, Firefox with about 10 or so dependencies took about 2 hours to compile on the PIII. Nowhere near a day. I'll bet that you (and others who say it took a day) had a lot more optional dependencies being compiled in.

That said, X is out of whack on the laptop. But I've only been working on that today and yesterday. Anyone figure out xorg.conf for a Dell Latitude C600? ATI Rage Mobility 128 and 14.1" TFT screen. xorgconfig and 'X -configure' give me a quite unusable xorg.conf. I startx and the whole machine locks up. No CTL-ALT-BKSPC to kill the x server, even. Have to hard shutdown the machine.

Anyhow, the magic of Gentoo is not really in setting CHOST flags (that is where the speed comes in), but in setting USE flags. I would submit that you get more of a performance benefit from having fewer dependency options compiled in than you get from having optimizations for your arch.

Well, that's all for now. Here we go X.

CPU's are alot faster than they used to be. decades ago, gentoo's install time was a major issue...

however for me (AMD64 3400+ and 600kbps internet) a stage3 gentoo install, plus emerge KDE took a lot less time that it would to download fedora core3.

I threw 2004.2 Stage 3 at a Dell laptop at work, just for fun. Don't recall any issues with X - installed flux to see what that looked like.
When I get back to the office I'll boot it and see if I can find anything obvious.