My Visual Studio IDE runs very slowly. Why?

I've worked with various flavours of Visual Studio 2xxx over the years, but mostly with 2010. Like most developers, I tend to remain comfortably behind the bleeding edge, and have only just started to use 2012. God help me, I only recently stopped using VC6. One thing I have noticed with Visual Studio, and 2010 in particular, is that the IDE can sometimes start to c-r-a-w-l. It can get ridiculously slow at opening menus, scrolling code, switching projects, basically responding to operator actions of any kind. I've had to trawl the net for fixes for this problem, and here I've collected together some of the most effective, in my experience. So, from most effective to least...

Clear Website Cache Clear out C:\Users\USERNAME\AppData\Local\Microsoft\WebSiteCache

You will need to go to Control Panel~Folder options~View and check "Show hidden files, folders and drives" to see the AppData folder.
Turn hardware acceleration off Go to Tools~Options~Environment~General and under Visual Experience, uncheck both
"Automatically adjust visual experience based on client performance" and
"Use Hardware Graphics Acceleration If Available"

...and scrolling speeds up. Weird: accelerating something slows it down. This might have something to do with the fact that my machine at the time had an NVidia Quadro board. These cards excel at handling large numbers of pixels, but not at moving those pixels anywhere fast. When I specified our new machines, I put in Nvidia 7-series boards, because consumer grade cards lke these can now deal with multiple monitors much better than they used to, you just need to check that all your monitors have suitable connections.
Stop Network Access Don't keep projects on network storage if you can possibly avoid it. Pretty obvious, but some people do it, particularly in corporate environments. I suspect if their managers were having to put up with the lack-lustre performance, the rules would be changed quite quickly, but that's just my anti-management prejudice showing again.
Clear ASP.Net files If you work with ASP.Net, clear out

C:\Users\USERNAME\AppData\Local\Temp\Temporary ASP.NET Files\SITENAME

For any sites you aren't working work on right now. NB: My observation about the hidden AppData folder above applies here as well, obviously.