Hi Brendan!
I just bought myself a 300 f/4 and was facing the same exact question this week...flash or tripod? The flash won and I should have the 580 EX II in a few days [].
So of course, take one off the list put one on the list ...abetter general purposelens or tripod? My budget is forcing meto look at more of the "gently used" merchandise for awhile.
Does it ever end?? [:P]
Denise
P.S. I hope you are enjoying your new lens as much as I am! []