i've been to hamburg twice! summer 2001 and 2004. My aunt lives there, so we like to go and see them.
it's a pretty nice city, although I must admit I haven't done most of the "touristy" things. driving there can be confusing, but it's nothing a map can't fix. After a month there, I had general idea of main roads and how to get around. I was actually doing the groceries for my aunt by the end (which was really just an excuse for me to drive the bimmer hehe).
check with your bank before you go and find out if they have any partner banks in europe. ie, with my scotiabank debit card, i can take money out of deutchebank(sp?) ATMs for a smaller fee than if I used other german banks. and I think it's actually a pretty big difference.
Oh, and in hamburg, you definitely must pay a visit to the St Pauli neighbourhood hehe. Even if only for sightseeing, it's very interesting imo.