208/220/240V normally interchange, 208 pulls slight bit more amps than 220, based on my exp with industrial motors etc, also 220/240 is standard house feed in US and Canada

Electricity Like Canada, the United States uses 110-120 volts AC (60 cycles), compared to 220-240 volts AC (50 cycles) in most of Europe, Australia, and New Zealand. If your small appliances use 220-240 volts, you'll need a 110-volt transformer and a plug adapter with two flat parallel pins to operate them

Wow, there's progress across the pond ;>)

I would say that on longer run multiCPU mother boards could save you little bit on electricity costs, also sharing graphical cards by various projects might be easier in multiCPU setup - some cores will do classical CPU tasks, others will get GPU.

I am testing the double Xeon Sun X4270 server blade. At full load it eats around 350W, each processor eats 95W, the rest goes to motherboard and a single hard drive - I pulled out all other drives and DVD. It is roughly the same as dual i7 CPU system. If you want to know more about this setup, let me know.

One of the best things you can do for your machines is look at your available electrical power.
A good UPS is well worth the investment especially when you get that day when your power goes on and off like someone turning a switch off and on ad nauseum.
I just upgraded from a 100 amp service to 200amp and the best thing I ever did.
Have a dedicated 40 amp 220 circuit going from the panel to a box on the outside ofg the house to plug in my 5500w generator in case we get outages like we did in Dec 2009 during an ice storm.
Then dedicated circuits to your PC equipment is also worth doing.
I have 2-20 amp/110v circuits to the areas where my PC's are located.
As to servers the issue is cost.
A good dual socket 1366 board runs from a low of $350.00 to over $500.00 Then you need ECC memory which is more expensive but again worth the cost.
Last is PSU's.. You really need to buy quality here and IMHO I would buy from just these companies: PCP+P,Corsair, and Zippy.
Dual and quad socket machines do cost much more but when you buy smart you can negate a lot of that cost.
Downtime is drastically reduced as these boards meet higher standards.
Losing 2-3 weeks production while your waiting for a RMA on a board is never recovered.
Same on memory,etc..
Buy quality, build carefully and do it one time and then sit back and let the machine do what it's designed for.
It pays off in the end.