For me,
I still prefer Slackware as well, the OS is clean, simple, and build solid. Everything in there is really stable and really good in quality. Not even a scar in it when i run the applications.
What i have done with my Slackware:
1. DHCP Server,
2. Backup Server,
3. DNS Server,
4. Router,
5. Software Development (CVS Server, Client app deployment)
6. Testing new features in kernel (It's really raw kernel from kernel.org) and many open source apps).
Lastly, software installation/removal is piece a cake man, just use installpkg, removepkg.
U can even download these packages which are supported from the net using "swaret".
And lately, wow, im doing encrypted filesystem (Loop-AES) and LTSP clients. All i need to do is just use what i have.