well, uhm, I see all users on gentoo haven't tried debian ;-)
quite interesting... just because afaik, the only reall difference that counts beteween debian and gentoo is the fact that debian is binary based, and gentoo source based.
but both dont have to deal with rpm, which is why they rock ;-)
I thought about gentoo, but I dont want to wait soo long for installation of packages. nice I can tune them, and speed up the system, but I'm sure I'd be upgrading every day, hence the system whould mostly be slow as hell (not a fast pc over here) so it whoulnt really work...
So I'd say gentoo is nice, but dont forget debian - it has the best *binary* package management system (well, except maybe for 'newbie's like autopackage and zero-install, but they dont have a distro backing them up), is quite fast, and has for sure the biggest package pool (I have 16.000 packages in synaptic, ready to install in a few clicks). also the choice you have: stable/testing/unstable/experimental - something for everyone ;-)
and alot ppl use debian (in one or another form, I think debian is one of the, if not the most used linux distribution!) which helps too (lot help available, for example).