Ginza is a good base for what you have planned, I stayed at the quite OK Tobu Renaissance (now a Marriot Courtyard) once. It gets a bit quiet in the evening but there are plenty of shops and restaurants in the area and is well connected to public transport. Also, it's very easy to get to the big fish market early in the morning.
Where to stay is certainly a matter of taste but for me, the most exciting and fun area of Tokyo, at least from the parts I've seen, is Shinjuku. There are around 10 huge major department stores there, hundreds of restaurants and shops and public transportation from Shinjuku station can't be beat, so many lines pass that station. It's also very lively in the evening. Navigating the area can at first be quite challenging though, the main train station is a gigantic maze which takes a while to understand and the amount of people buzzing around there is just amazing. Don't go to Shinjuku if you're looking for peace and quiet
Shinjuku is sort of halved by the train tracks, the west side is the skyscraper area where some of the larger hotels are located, the east is for shopping, entertainment and restaurants.
A great place to check out opinions on hotels all around the world is
Reviews of vacations, hotels, resorts, vacation and travel packages - TripAdvisor . Reading the reviews there will give you a pretty good idea what to expect. But all in all, I don't think you'll make a mistake with the Crowne Plaza, especially in regard to the price, it won't be easy to do much better.