As I remain solidly behind the curve, I use a bunch of old Macs. I like Firefox, and the speed difference in the new version is pretty impressive on the PC at work. None of'em are Intel-based machines, however, and Mozilla has left them behind.
TenFourFox works on my G5, while the frighteningly-named Minefield works reasonably well too and covers the G4 laptop. The most important extensions still seem to work fine, though I lost PassiveCache (which I liked a lot). Not really sure which is peppier; maybe M. Bouffant's page is the true test?
Hmm, Minefield seems to do better with Flash, so sticking with that.
OMG I did not know what Bouffant had waiting there at that page over thereabouts.
I'll get you for this Weigel. YOU'LL MOO THE DAY.