I agree that vista is bloated, I'm running vista ultimate on an alienware and I just don't see the advantages that it has vis-a-vis its size and system space. However, the fact is, it is the new standard and microsoft will keep producing items just for vista: such as Direct X 10, which is solely for vista and which all the new games will be running.
In your case, my suggestion would be to keep vista, but clean up a few things. First and foremost, get rid of Norton, I completely hate norton, another bloated program and not even close to being the best on the market. Get NOD32 or kaspersky. They are much lighter and do at the very least as good a job as norton. Also when removing Norton, do not use add or remove programs, get the Norton removal tool from their site so it completely removes this beast.
I would also use msconfig to shut down all the unnecessary programs at startup and whatever unnecessary services are running. There is no way you should be having close to 100% cpu usage even with vista. Most likely there are just too many background programs running. You should have programs running when you need them. If your computer is clean of viruses and spyware, doing this should improve things a bit.
A hardware suggestion would be to upgrade your memory. memory is relatively cheap and it will help vista run better.
