[doc4t]

Since so many are complaining about the difficulty of developing/debugging in IE here is a couple of links that should make it easier for you

Internet Explorer Developer Toolbar http://www.microsoft.com/en-us/download/details.aspx?id=1835...

VPC Images for XP/IE6, Vista/IE7, Win7/IE8, Win7/IE9 - you can import the images to VMware and VirtualBox http://www.microsoft.com/en-us/download/details.aspx?id=1157...

MS Script Debugger and how to http://blogs.msdn.com/b/ie/archive/2004/10/26/247912.aspx

Detecting Memory Leaks http://blogs.msdn.com/b/ie/archive/2007/11/29/tools-for-dete...

VS Express (free) http://www.microsoft.com/visualstudio/en-us/products/2010-ed...

Firebug Lite http://getfirebug.com/firebuglite

I'm sure there are more some where...

[NelsonMinar]

Microsoft's virtual machine images work great in VirtualBox. It's a bit of a PITA setting them up manually, but it's very easy with the installer shell script at https://github.com/xdissent/ievms#readme

[xutopia]

I prefer the ISO than the images for Windows 8 Consumer Preview => http://windows.microsoft.com/en-CA/windows-8/iso

[vbigham]

Props for posting these! Now we need to turn this list into blog posts.