Hmmm, I haven't noticed these problems. Have you read anything online about these being common problems?
Yes, the HD issue was first noticed in Vista, and apparently not resolved.
1. Do you use opera? Because if so, that maaaaaay be where your space is going. Also, go to start menu and type in %TEMP% and clear that out.
2. Monitor flicker is usually a video driver issue. Try updating if possible.
I switched to Windows 7 64bit last night, happiest I've ever been.
No, I use Firefox, and I have CCleaner setup to clear my temporary files on start-up.
My video driver is updated to the most recent Vista driver, 'cause there is no Windows 7 driver available.
Edit: Well, I'm fed up with Windows 7, and went back to XP. I also found out that Microsoft will continue supporting XP until 2014. That's plenty of time to wait on Windows 7 SP1, which is due in November.