Re: power supply
What do you mean when you say "standard power supply"? Is it a power supply out of a name brand pc or a custom built pc? If its out of something like a dell or gateway, it probably won't fit in an aftermarket case like the one you are planning to use. And based on how old the power supply is, it might be a 20 pin instead of a 24 pin, and you'll want to check to make sure that it has the extra 4 pin power for the cpu as well.
I ran a setup close to that on an Antec 500w power supply and it ran fine even with a couple extra hard drives in it even though the motherboard called for 600w so I'd say if you have to buy a new one, 600w will be more than enough.
When all else fails...Ham Radio!
I still have the same old HP DV9700T laptop I've had for years...still kickin'