Power Supply Upgrade Q

I think I already know the answer to this but no harm in asking for someone else's opion. I'm considering upgrading my power supply from the current 250 watt (completely inadequate considering my wife's system has has taken a nose dive) to one of these three:
CWT 420W Dual Fan PS w/ auto temp control (1) or
350W DUALFANS POWER SUPPLY FOR P4/XP BY TOPOWER
350W DUALFANS POWER SUPPLY FOR P4/XP BY ENERMAX

Considering my system specs (see lower) is there anything I should take have in mind before trudging off to the store and doling out the cash? What I mean to say is by upgrading, way up, am I putting my system at risk?
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* System Summary *
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Processor: AMD Duron(tm) processor 900 MHz
Math Support: Present
BIOS: VIA694 - 42302e31 Award Modular BIOS v6.00PG, 10/18/01
Bus Type: PCI, ISA, USB
Ports: 1 Parallel, 2 Serial
Memory: 512 (13% Utilized)
Floppy Disks: 1.44 MB
Hard Disks: 9.55 GB, 37.28 GB, 37.28 GB, 37.28 GB
Multimedia: Sound, CD-ROM
Video: NVIDIA GeForce2 MX/MX 400 Ver. 5.13

< Operating System >
Windows: 5.1 (Build 2600)
Once I have integrated my wife's peripherals on my, I guess now it's our, system we will have 2 printers (1 USB 1 Par Port), 1 Scanner (USB), 2 USB Hubs (powered), 2 PDAs (USB) , 1 digital camera (USB), Hard Disk Drive Cooler - 3 Fans, another video card same make and model (now I can have 2 monitors :), router

Either of the 350's should be plenty, but if you want to feel safe the 420 should be overkill. My 420 sure is.

I'm using the 350 Enermax with a 2.4 P4, 4 HD's, 3 optical drives, sound & powerful graphics card, and there's no strain on it at all. It's got a nice feature where you can adjust the fan speed to make the PC a bit quieter if you want.