I've just migrated to fedora from slackware.
Slackware was great. It's about as close to bullet-proof as any OS I've seen. If I were to build a server dedicated to one or two tasks, (FTP, HTTP, SMTP, etc.) it would probably still be my choice.
But I want to experiment with different, new, cool stuff. And for that I need support and standardization. It seems like every time I wanted to try some new software, the readme file always had specific instructions for Red Hat/ Fedora and Debian/Ubuntu. For everything else, you're using the source and having to figure out the makefile and modify it for your distro. I get fulfilment out of using software, not installing it.
My first linux install was seven years ago, and it was Red Hat 7.0. (The cd was in a book I checked out from the library.) I've been a linux fan ever since.