A lot has been said on here about this phone, but I'm surprised to find very little of it concerns the phone's excellent features to help with exercise. I bought the phone because I wanted a better camera than on my old Sony, but quickly found that it had a built in pedometer which has changed my life. Without me having to do anything, remember anything, it accurately records how far I've walked in a day, so that I finally found out what a couch potato I am.
So with my phone in hand, I started off walking trying to hit 5000 steps a day. Honestly, using the phone I lost more than half a stone in three months and also am just fitter generally. It also has settings for running, measuring roughly how far you've run, and awards you virtual medals when you hit a new high. Now this may sound silly, but actually it's fantastic. It really is. Silly things can motivate you, and I found it really good.
It also has an absolutely huge memory for photos and video, which has several times been extremely useful with work.
The only downside of this phone is that actually it's not the best quality speaker in the world, and often I have trouble understanding what someone is saying on the other end! But exercise-wise it's a great phone and I wish Sony would hurry up and make an updated model, i don't want to have to switch brands...