The eXtreme Power Supply Calculator contains 600+ CPU including latest processors from Intel and AMD such as Conroe, Intel Core 2 Duo, Intel Core 2 Extreme, Intel Core Solo, Intel Core Duo, Intel Xeon, Intel Pentium, AMD Athlon 64, AMD Athlon 64 FX, AMD Athlon 64 X2, AMD Opteron, AMD Sempron 64, 939, AM2, F and LGA775 sockets and latest graphics cards from NVIDIA and ATI such as GeForce 7900 GS, 7900 GTX, 7950 GT, 7950 GX2, Radeon X1900 XTX, X1950 XTX, graphics cards from EVGA and Gigabyte and more. Power supply calculator has the ability to select hard drive type (IDE, SCSI, SATA), NVIDIA SLI or ATI Crossfire technology, cooling fan, PCI card, external device, USB and Firewire, water cooling kit and components, etc. This version of eXtreme Power Supply Calculator determines the overall computer power supply wattage for your desktop computer, server, computer racks or any pc computer system that uses ATX power supply.

Extreme.Outervision (http://www.extreme.outervision.com/psucalculatorlite.jsp)

That's really cool!!

System Type:
Single Processor
Motherboard:
Regular - Desktop
CPU:
AMD Athlon 64 3700+ 2200 MHz San Diego 1.35v
CPU Utilization (TDP):
85% TDP
RAM:
1 Stick DDR SDRAM
Video Card:
ATI Radeon X1900 GT
Video Type:
Single Card
SATA HDD:
1 HDD
DVD-RW/DVD+RW Drive:
2 Drives
56K PCI Modem:
Yes
Additional PCI Card (avg):
1 Card
USB:
2 Devices
Fans
LED:
2 Fans 80mm; 2 Fans 120mm;
Keyboard and mouse:
Yes
System Load:
100 %

Recommended Wattage:
325 Watts

Another cool link, gj F1! ;)
I particularly like the part about the importance of 12v and 5v and the rails.
a PSU with a 80AMP 12v output but on a 4 rail system is a lot less desirable than the one with 70/60AMP output based on a single or even 2 rail system.
People should also know the difference of maximum output Wattage they normally seen on the PSY means nothing if the average output is laughably low. Also review the certifications the PSU obtained on what tests it passed!
Also a label indicating 'AMD/Intel Recommend' is not the same thing as 'AMD/Intel Approved'.
I don't care for spending a bundle on name brand components just case but in the case of PSU, going cheap is almost always a sure way a big headaches down the road...PSU, Mobo and RAM are the 3 most important components andt should try to purchase the best you can afford! ;)