Good Tokyo neighborhood for a first-time, 40-year-old solo traveler?

I live in NYC and I've done a lot of European travel but this will be my first time in Japan.

I love walking around, trying street food, coffee shops, fun small bars, and popping into fun-looking shops. Nightlife is a bonus but I'm too much of an old man for nightclubs.

I'm a fairly mid-range budget traveler so I'm not looking for luxury but I'm also not looking at low-budget either—this is my 40th birthday gift to myself so I want to be comfrotable.

I'm comfortable using public transportation but I'd rather not have to use it for long periods of time if it can be avoided.