Which POWER SUPPLY for AMD64bit High end System?

Could someone please recomend a power supply with enough power and stability to run a highend multimedia 64bit AMD system, with enough voltage and power for futre uprgades.

Is a 500 watt too much, possably leading to unstability or even damage. Ive been running a 400 for 2 years (runing older tech from back then), and can only think I would need more power with the newer tech?

Your thoughts?

400w would run the system with no problems (it was way more than you needed then, its about right now), though your overclocking would be limited, and future upgrades might be too. Increased capacity is only a good thing. The 500 watt psu can handle a greater load, but it is still providing the same voltages, an d thus won't hurt anything. Do be sure to get a good name brand psu. Blowing the power supply could take all or most of your other hardware with it, so don't try to save a couple bucks. Antec, Enermax and Zalman are some good brands

Thanks heaps,
I like having the option for all the extras, so I might settle on a Good Brand name like one of the ones you have metioned for sure.

I dont mind spending the extra, as I read also about loosing much of the hardware if a cheap supply does blow out on me.

I,ve seen a few good 480w ones about. I,m saving a hundred by getting a thermatake case of ebay, and will put that towards the extra on a top notch power supply. Thinking of getting a thermatake one to go with the case, but have not really heard much about them in reviews.

Thanks for your comments