I'd say go with whatever works for you, and if that's Slack, stick with Slack. I think you'll find that any Linux distro has everything you need for most tasks, including server applications. It just boils down to whatever you're comfortable with.
Third, Maybe with your experience I can pose a question about Linux Slack10. I also have RedHat linux 9.0 and 7.2 (3 iso cd with 9.0) but have found them difficult to install. I have had that system installed once before and was able to connect to the net, With Slack, I have not been able to connect. Would you recommend using Redhat on should I continue with My slack setup?