Akihabara

Akihabara is best known its electronic stores. There are a number of large chains with stores there, as well as much smaller stores. The chain stores have branches elsewhere in Tokyo and thruout Japan, so it’s not that big a deal to visit Akihabara anymore.
Why shop for electronics here? It’s not price – you’ll pay about the same or more as you would in the US, and you aren’t getting the US version. It’s usually not to see the newest things – I found the products on display were the same as were available currently in the US. I was actually intent on buying a cool new watch, and couldn’t find anything I hadn’t seen before in the US.
The best reason is because these stores have everything out where you can see and try things. They’ll have the cheapest to the most sophisticated/pro model out. They’ll have all the accessories. You can play with things here, the buy them at home.
There’s no reason to go thru every single chain store (Ishimaru, Sofmap, Laox, Yodobashi, etc). They are all the same. Pick one.
Beyond big-box stores
I had the most fun going thru the Radio Market, a collection of booth-sized stores that sell all kinds of things, especially unusual components (photo above). It’s also fun to see all the costumed-up people trying to get you into their store:

There are also anime-oriented stores, if that’s your thing.
Shinjuku
Shinjuku is known for many things, but we went in the evening for one specific thing: to go to the observatory on top of the Tokyo Metropolitan Government Office. It’s a few blocks from the Shinjuku train station. There are 2 towers and there are observatories on both. Only one is open in the evenings, which is when we went. The views are great. And it’s free!
