Thanks for the info. We're just taking a day in Pisa to de-jetlag; the logistics work well. See the tower and the basilica, yadda, yadda. I'll be in such a fog that it won't matter! I've been to Florence twice and agree with you, but I'd rather go in the spring or fall when you can actually see something besides the back of other tourists' heads.
Spring is the best time to go! Not too hot and everything is still green. Those things in Pisa are nice ... I found the grave area behind the basilica to be the most interesting.