About 64-bit Linux?

As my Fedora project is proceeding relatively well, I am now seeking advice re: 64-bit Linux. I have a desktop I built myself utilizing one of the early AMD 64-bit chips on an ASUS K8N mobo, using nVidia GEForce FX 5200 AGP and ASUS mobo bundled sound (RealTek AC’97 Audio), Plextor CD/DVD-RW and NEC CD-rom with [I think] Seagate and Western Digital 80G HD’s (ATA).

Also, I am thinking about dual-booting this system between XP (current C) and secondary drive (current D). Is there any reason to NOT just leave XP on current C and load whatever Linux to current D drive?

edit-thought about adding something but changed my mind