After 3 years running with the same system (XP 64 bit), I finally decided to move on - and install Windows 7 Pro 64bit. I had been waiting for this step in order to also move to VS2010.
So the OS is super-fresh, the hardware is a little old but still decent (quad-core, 8GB) - and this damn VS2010 gets so slow that after a while I need to restart it (3-4 times per day).
Granted - I also installed R# 5 which puts a lot of pressure on the machine. So I disabled it, but still, even scrolling a 1000-lines file is slow !!!
Searching the Internet didn't help - I only found other complaining like me.
So I started digging into the Tools ==> Options, and found out, under the "Environment" option, that VS2010 tries by default to make use of hardware acceleration wherever possible. I thought "hmm, maybe it's not as good as it thinks in using the HW acceleration?".
I disabled the acceleration and got a HUGE performance improvement!!!
Re-enabling R# comes at a cost, but at least I can work (I've enabled in R# the option to show the amount of virtual memory used, and once in a while I call GC with a right-click and it runs much faster for a while).