I always come back to Debian. It’s a love affair 
And you can optimize source (using apt-src, for example), but I just don’t have time for source-based distros these days 
Debian, netBSD, freeBSD, SAM (sam.hipsurfer.com)…
tried Gentoo, mandrake (never worked on my computers… sort of curse I guess), suse (idem), slackware (my first linux…), fedora, crux and a linux from scratch (rather hard to maintain, but really one of the best option).
I use Gentoo. Debian’s good, I hear lots off good about Ubuntu. Might get around to trying a BSD sometime.
I actually use Debian testing, but I plan to use Gentoo on my future desktop…
Started Red Hat 8 … then they stopped supporting it
Upgraded to Red Hat 9 … then they stopped supporting it
Installed Gentoo … adios Red Hat! 
Next step is to make Linux the default for my wife as well … then kiss Windows partition good-bye!
I use Debain Sarge (stable)
I tried others distros (gentoo, slackware, suse and a few others) but I always came back to Debian
Debian rocks
So I do.
I have been using arch linux for over a year. Bought another drive and now running gentoo and ubuntu along with arch. Used gentoo for a long time before I switched to arch.
Gentoo all over the place!!! 8)
I’m using Debian unstable (but it’s very “stable” nevertheless 
) at my job and at home, it’s the perfect distro for me.
I’m using some Mac os x too.
I have been using Linux since 1997. I tried many distros but haven’t used any other than Arch Linux since 2003.
archlinux.org/
Currently I am developing an Arch Window Developer based in FVWM.
Read more:
viewtopic.php?t=807
fedora core 4 here.
I’ve two machines running Arch Linux, one with FreeBSD (m0n0wall) and a server running Sarge. I’ve tried many distros in the last years and the ones I like most are Arch and Sourcemage (unfortunately I hate compiling everything on my own and Sourcemage is source-based, but it’s a great distro anyway).
crux is my cup of tea
Another happy Gentooer
Cheers
ArchLinux, Debian Sid, Debian Sarge. Sometimes I play a bit around with Slackware, Gentoo or other distros, but I always come back to Debian, because it’s what works best for me. I also run AIX on littleblue (but I boot it seldom).
Gentoo, for binary distros I like Debian by far the most.
Another ArchLinux user here.
I’ve tried plenty of others multiple times but always revert back to good ol’ Arch. Now, if it were to go away forever (ouch!), I’d probably go back to using Gentoo, or Slackware.
Try KateOS… stable as Slackware + Updateos (similar to apt-get) + packages TGZex (easy updating distributions + installing programs)… Nice distro.
Gentoo all the way, I would prefer not always compiling from source, but considering that, gentoo is still the one and only distro for me (well from all that I’ve tried atleast)