I prefer to use Studio 2009, but some clients have projects which require 2007 to complete or process.
I was using a separate computer to my main working computer to do this as I had problems getting 2007 to install on a Windows 7 64-bit system – this was inefficient and somewhat annoying as to move files between the two involved the network storage or a memory stick. The answer was amazingly simple – use the Windows XP virtual machine which comes with Windows 7 as standard. Problem solved.
I hope that SDL 2011 when it arrives later in the year will prevent the need to run 2007 at all, but if it does not – it does run OK in a virtual machine.
An addendum to this post.
While this worked for the installation and subsequent use, the fact that the licence from Trados was not recognised on subsequent starts meant that I had to resort to using Trados 2007 on an older computer system. Happily, the new 2011 Studio version is much more compatible with the older 2007 version and I have not had to use the 2007 version since the new one came out.