Wow, sounds good as far as your old computer vs my current. I think mine would be generally slower. So an upgrade sounds exciting!
I've been running W7 x64 sine the beta was available, and now the RC, so in total for half a year, 8-10 hrs a day, and I've never experienced any issues even remotely like yours. In fact, I've really never experienced any issues at all. W7 runs perfectly stable, as Vista did for 2 years before that, XP for years before that, and Windows 2000 for years before that. In 9 years since going to an NT based OS (Windows 2000), I think I've only had 1 blue screen of death or system crash, taxing my system heavier than most, every day, all day.
The only "bug" I found with W7 was that if you use a monitor profile generated by Windows' built-in calibration software, the picture viewer becomes veeeeery slow and sluggish. But I just switched to my hardware generated colour profile and now it's fine.
Yes, I must admit that over 15 years of using Windows PC's I've very rarely encountered the 'blue screen of death'...but I have had more crashes than I can shake a stick at due to low system resources and poorly written, memory hungry software. I'm always trying 100's of different programs out, video editing, picture editing, plugins, picture resizes, downloaders...the list goes on and on....some of them from spurious sources - not many of them actually turn out to be keepers - probably 1%. So you can imagine what my poor registry must feel like
Even though I would run CC cleaner, registry mechanic and various spy tracking software every day, eventually a fresh install is called for- and with XP Pro that was becoming a nightmare what with all the security updates and patches required. It would take 2 days to do an install and update and 30 reboots!
The new build PC was working great for a couple of days, as far as explorer stability goes...then as I loaded more and more software on to the system, it went pear shaped at some stage and started having the same old issues opening and displaying 'my computer'. I'm definately not alone in this, I have found a few threads displaying exactly the same problems and the only solution seems to be to remove all your software until you find the cause.
How very Windows...
OSX dual boot is an option I suppose