We haven´t booked a hotel for Hamburg yet. Our cruise ends June 2nd and we haven´t decided how much time we spend in Hamburg.
Last time (2 years ago) we stayed in the Crown Plaza Hotel (Graumannsweg 10 = street address). We got a good deal there, breakfast buffet included. It is conveniently located close to the Alster lake. A bus stop is next to the hotel and a subway station is within a walking distance. I just checked it for our trip but rates are too high.
Etap and Ibis are low budget hotel chains over here. And they usually have some nice downtown locations. I´d avoid St. Pauli (red light district). We´ve stayed in that area years ago in a really nice hotel. DD was less than 2 years old so we didn´t go out at night anyway but that´s an area I´d avoid at night (except the main tourist street there, but the hotel was in a small side street).
Order free brochures (including city map).
The main attractions of Hamburg are close to the Harbor (Landungsbruecken) and the Alster (lake, river). So I´d take a hotel in that main area next to a subway or suburban train stop.
The public transportation system is quite good (not as clean as in Munich, but save)
Also check the Hamburg Card which includes public transportation and discounts to many attractions (doesn´t pay off if you stay less than 3 days).
This is a great hotel overlooking the harbor (but not inexpensive)
This one is also nicely located along the Elbe river at Finkenwerder (you need to take the ferry to get downtown, also not inexpensive)
You need to take a harbor cruise. Just go to the Landungsbruecken. There are a lot of offers there. There´s also a Hop-On/Hop-Off bus starting next to the Landungsbruecken.
Here are some of the bus companies
If you love model trains you have to visit