Newbie Help Needed

[Roduga]

Evening guys and girls. It's not often I stray into this area but a new PC has arrived:

AMD Opteron UP 175 Dual Core San Diego 2.2GHz 2MB Cache (Socket 939)
DFI LanParty UT NF4 Ultra-D (Socket 939) PCI-Express Motherboard
Connect3D ATI Radeon X1900 XT-X 512MB GDDR3 AVIVO TV-Out/Dual DVI (PCI-Express)
Western Digital Caviar SE16 320GB 3200KS SATA-II 16MB Cache -
NEC ND4551 16x16 DVD±RW Dual Layer LabelFlash ReWriter (Black) - OEM
Arctic Cooling Freezer 64 Pro CPU Cooler (Socket 754/939/940)
Enermax Liberty 500W ELT500AWT ATX2.2 Modular SLI Compliant PSU
OCZ 2GB (2 x 1GB) PC3200 Dual Channel Platinum Series EL-DDR CAS2
CoolerMaster Praetorian 732 (with blowhole)

I'm not looking to squeeze every last bit of power out. What tweaks/OC should I do without risky stability?

 

[Roduga]

if your worried about instability just test it plenty when you overclock

*cough* Newbie *cough*

I don't even know where to start!