Usually spare change and/or my Oyster Card (touch in bus pass) in my jeans pockets. I keep cash in my Oyster Card holder, so it serves as a very flat wallet too. In my back pocket, I keep my iPod when I have it with me - I don't like it in my front pockets when I'm walking because it digs into my <pelvis/hip?... dunno. But it hurts.> (the big 30GB one).
In my coat (the brown leather one I've been wearing a lot lately - my others don't really have pockets), I keep my phone. It's got zip-up pockets, so it's safe.
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