Mandrake is the easiest, has the most bells + whistles, while RedHat tends to be more tested and less cutting edge (for corporations, etc).
You may try Knoppix, which is a live linux on cd. You boot and run right from the cd. Don't even need a HD in the system. Full GUI (Debian X-windows), wireless support, Open Office, etc. Good way to learn Linux without having to install it.
Plus Ça Change, Plus C'est La Même Chose.
Windows XP SP2
AMD 64 3000+ CPU
1GB DDR 400 PC3200
Pioneer 106D // Yamaha F1
ATI Radeon 9500
Dazzle PCI-DVCII Capture Card
FIC K8-800T / Antec Sonata Silent Case
(2)Maxtor 120gb, IBM 120gb, 80gb, 60gb Maxtors
(2)Seagate 200gb SATA drives on VIA SATA