I'll be there this summer again. I actually didn't enjoy it when we visited in 2007, but we were on a Trafalgar tour and all I remember is spending way too much time visiting churches. I do remember walking through a row of shops that reminded me of Rodeo Drive, along with associated prices. I'm hoping it will be a different experience this time. What do you recommend doing there?
Florence is mostly about the Renaissance, which is all about the art from that time period, including the churches. For me, while the art is incredible, and the food is top notch, the city itself doesn't have enough to make the insane crowds worth the headache for more than a couple of days. Once you've seen the Uffizi and a couple of cathedrals, the list of must-sees gets quite short. But I also prefer the more vibrant and maybe gritty side of Italy, cities like Rome, Naples, Genoa, etc. and find Florence a bit... boring, I guess? I also find it very American, full of well off students on a year studying away. This is obviously personal preference, as I know far more people who hate Rome (my personal favourite) than dislike Florence.
If Florence itself isn't for you, Tuscany offers a lot more throughout. It's popular with visitors for a reason. As I'm sure you know, it's insanely bucolic, rolling hills, cedar-lined roads, villas on hilltops, vineyards in the setting sun kind of stuff. If the crowds and high-end consumerism of Florence isn't for you, maybe look for an agriturismo or similar home base, rent a car, and drive around to the dozens of picturesque Tuscan villages on nearly every hilltop and do some exploring. Siena, San Gimignano, Arezzo, Lucca will all have quite a few tourists as well, but nowhere near the crush of Florence. And unless you speak some Italian, it's not a bad thing to have a few fellow tourists around to make a place easier to visit (and have some public washrooms easily available). I'd personally skip Pisa unless you desperately need a picture of you pretending to hold up the leaning tower, though.