I've had a minor epiphany in the last week or so. For some boneheaded reason I never caught onto TestDriven.Net's "Repeat Test Run" feature until I saw somebody mention it on a comment to Ayende's post. I promptly went into VS.Net and set up keyboard shortcuts for "Repeat Test Run" & "Repeat with Debugging." No more hunting around in the open window list trying to get back to the test fixture, just go "CTRL-2" or "CTRL-3" (my mappings) and run the last test. Anything that makes the mechanics simpler just frees your mind for the meatier thinking work.
It's a deceptively simple looking tool, but there's goodness galore in TestDriven.Net.
Tips on setting up the keyboard shortcuts: