My long run has always been on Sunday mornings for as long as I can remember. This allows me to lie on the couch or bed and recover all day. SInce college I have been racing on Saturdays and then running my long run the next day. Lately I have been reading a lot of articles about the hard-easy principle. Do people think its bad to run your long run the following day after a race?
It really depends on how hard you go on your long run. I never believed in the long slow run on sundays. I always run it more as a progression run. If you race on saturday and you still want to get a long run in i would say go a little shorter and slower on sunday. If you normally go 20 miles back off to 16.
I'm a big fan of race (or workout) Saturday and then long run on Sunday. That's what works in my schedule and I like to recover all day on Sunday. If you do this, make sure that you take Monday and Tuesday easy. The schedule I was thinking was Wednesday intervals, Saturday race or tempo, Sunday long run (either easy or progression)
Jack Daniels talks about this in Jack Daniels' Running Formula. He does say that hard/easy should be the plan, but that can also mean 2 hard days followed by 2 easy days. In Advanced Marathoning by Pete Pfitzenger, Pfitzenger also puts a race on Saturday, long run on Sunday a few times in the schedule since it's good to do your long run on tired legs.