I'm in the States very often (2 weeks out of every 4) so I often look at things I can bring back home. I recently bought a PS3, so of course I was tempted to by it in the US. However, although it would work, the hassles and the price don't really make it worthwhile IMHO.
The price a at Amazon.co.uk is 279.99.
In the States the same spec is $399.99 (204 pounds). However - most states over here have sales tax on top of the advertised price. I'm in California where the tax is 8.5% - so that's another 20 quid. You have to pay shipping and might have to pay some excise duty. Then you have to buy a power cable. Your warranty position is a bit dodgy, and some UK DVD's won't work. OK - maybe you could save a few quid - but is it really worth the hassle?