Bill,
My old system took nearly 5 minutes to boot! Now the new one takes less then a minute. Both systems are loaded the same. When Hal loaded under XP there would be skipping in the voice, I'm assuming it was the slower disk drive. Vista does require a power house to run, IMHO it's worth it. There are times I would like the openness of XP. I have not noticed any application not being compatable so far with Vista. I like the performance analizer compared to the old task manager in XP.
But like I said before I bought a real powerhouse and it's not fair to compare it to my old computer, it's not apples to apples. I have noticed with nothing running Vista uses more memory than XP, but with the cost of memory today, what the heck I have 6GB and the max I've used so far is 4GB. But that is why it runs faster less disk cacheing the whole operating system can be loaded, network operations are faster, it may be a pig but it's a fast pig.