There is not a day goes by where I don't use a virtual machine for development or testing.  Same goes for Remote Desktop.  I couldn't work without either.  However, remoting into a machine - be it real or virtual - means I lose the benefit of having dual monitors.  VMWare supports dual monitors I'm told but we use Virtual PC and Virtual Server.

But, never fear, /span is here!  Yes, if you launch Remote Desktop aka MSTSC.exe (Terminal Services Client) using the command line switch /span then it will extend the desktop across both monitors.  This is not the same as dual monitors - it's really just making 1 really wide desktop - but it's good enough for me.  Now I can develop on virtual machines almost as well as real machines.

Oh, and in case you didn't know, you can also use /console to connect to an existing session on a remote machine.  This is as close to a real login as you can get.  You may also find this necessary when installing software.  Some application installs will tell you it cant run when your logged in remotely - /console will bypass this.