Servicing a PC that's running pretty hot and I'm not sure why.

P4 2.8 800MHz bus
Intel 865PERL motherboard
ATI Radeon 9800 128M video
2G DDR 400 RAM
120G Seagate Serial-ATA hard drives X2 (Stripe RAID)

I'm running one extra rear chassis fan and two front chassis fans by the hdds. The hdd's seem to be running nice and cool. The rear exhaust seems abnormally warm. the video card runs pretty hot even when the system is idle.

When I run a cpu tester, the system temp utility reports the cpu at 63C (warning threshold default is 68). The system temp runs at 54 (threshold at 50). with all the ventilation it's got, this doesn't seem normal, does it?

FYI, I'm using a Zalman quiet power supply and cpu heatsink/fan.

What temperature should a PC run at comfortably?