Tokyo, the tale of many suburbs.
Tokyo varies a lot depending where in it you go. Being a geek from Melbourne I found Asakusa and Ahihabara to be very much to my liking, where as avoided Ginza and its expensive restaurants almost completely. Harajuku and Shibuya is a must see if fashion is your thing, just make sure you let yourself go into the back streets of Harajuku. I also found Tokyo to be quite safe to walk around in the evenings, which was very pleasant in mid-spring (and allowed you to dodge a lot of the crowds.)
Insider Tip:You can eat quite cheaply if you stick to the local cuisine. I often had tasty and filling meals for under $20aud, including alcohol. Also, data sims are life savers for navigation as paper maps don't cut it, just check for excess data charges.