wow...well that'll certainly make a difference.
I won't be able to help you much with the motherboard, but all you have to check on sites is that it supports the pin of the processor you want to get. Because it all depends on features. You won't want for example one with onboard video and sound possibly (these tend to be rubbish), thoguh most come with them. Then there are all the different chipsets like LAN, and USB ports, etc, which you should be able to make a discion on based on features vs Price.
As for the PSU though, you want to aim for around 400 watts, 450 if you can. Anything higher for a system usually will just be wastage, since all the components together wouldn't use that much, for example if you only had a basic system with nothing else plugged into it. So yeah, those wattages are fine. If you have to, get 500 Watts just to be sure.
I'd post on here with makes of some you like since the PSU is very important in a system. A bad one could underpower it, or even crash or damage your system if it went, or got unstable.
I hope this helps