Well the fancy effects require a decent vid card as teh OS tries now to off-load as much as possible. SO that hits folks most.
But next comes the extra protection of the new internal security model and the user-space drivers. I expect we will see newer/better drivers developed as the Vista sales increase and developers see a growing user base.
But yeah "bloat" as it's called -- or more precisely fast coding My first program commercially sold was in 1976 !! I selected which part of memory each instruction went in to because the "memory" was actually a rotating drum. Each instruction had an execution time and so you wanted the next instruction to be coming under the drum heads as the previous instruction compelted. Could take hours of manually optimising but in the end coudl run 100 times faster if got it right !!!
Nowadays, we have become used to Moore's Law so know that in 18 months it will be twice as fast, twice as big and so why spend valuable development $$$$ when the problem goes away so quickly.
Despite needing new h/w investements many businesses will do so as soon as VIsta proves stable. Mainly for the vastly reduced costs of netwrok deployments. Vista requires a fraction of the effort of XP or NT/2K. So business can save a fortune by spending a little Not to mention new hardware is getting smarter on power consumption and usage, if you have 70,000 PCs on the company desks and can save a few dollars in electricity it all adds up !!!
"A woman without curves is like a road without bends, you might get to your destination quicker but the ride is boring as hell'