Touch+Windows 7
Horrid. Currently Windows is not worth even thinking about for tablets because of the interface.
And contrary to your last point, Windows 8 appears to be using less resources then Windows 7.
I shall be putting that to the test on a HP Tx 2000 (1.9ghz Dual Core, 3GB, HD3200 laptop from 2007)
Had Vista, nuked it for 7. Runs fine, lets see how 8 pre-beta fairs