I haven't used Debian so I can not comment on there release. Right out the gate I see one issue in using Gentoo/Slackware distros and that is the install process. If Red Hat is your first/only distro that you have used then you will be in for a bit of a ride. Slackware is a bit easier but neither one of them are GUI based like Red Hat. Both Gentoo and Slackware have very informative docs on how to get each installed and configured. I'm sure with patience, time and the "How to" printed off you'll get one of the two installed. Personally I would go for Gentoo.
AMD T-Bird 1.33, Abit KT7-RAID, 2- 80 GiG WD ATA 133 7200rpm HDDs Running Raid 0, Fortissimo II, Sony DVD+RW, ATi Radeon 7500 AIW.
eMac,G4 700 Mhz, 256 RAM PC 100, 40 GiG HDD, 16x CD-RW, 6x DVD,GeForce 2MX.