well i say slackware is good and i will say why...
1. Simple internals
2. Very responsive compaired to every other distro ive tried
3. Easy to configure (at least for me, since u used gentoo then configuration shouldnt be hard for u)
4. Slackware is very stable. I've used fedora core 3 and some other lesser known distros and ive never had slackware crash or freeze on me although fedora core 3 froze on me about 3 times in a week (i tend to abuse my OS, lol)
5. u can easily get slackware setup with the bare minimum.
id suggest u check out the server distro im working on. it isnt fully finished but it would be a good base for you to start with (LDIOSse).
its based on slackware 10.1 but has recent packages and kernel and the update process will be simple:
if a package isnt available in the repository, u could check out the slackware package browser for a lot of packages. could also check linuxpackages.net
install a package with:
NOTE: LDIOSse automatically starts apache, mysql and others at startup. to stop this (you might in ur situation) just edit /etc/rc.d/rc.local to remove the startup command and remove the server package (all one package for easy use and removal as needed.