[Update: link added for the back of the map]
One thing I couldn’t find online before the trip was a good map of places to go in Akihabara. The ones I did find were either inaccurate, incomplete, not to scale, required local knowledge, and/or were drawn with complete disregard for the Western notion that North should either be at the top or clearly marked.
The time I spent marking things up in Google Earth did help me find a few places, but it doesn’t produce useful printouts, so I couldn’t bring it with me as PDFs.
Fortunately, less than ten seconds after we stepped out of the station, a pretty girl in a maid costume handed me this (3MB JPEG). The back side of it has more ads and a sorted list of shops and their block numbers.
This is apparently produced by the folks at Akiba Guide.
[Update: Oh, yes, North is to the right, and in Google Maps the area looks like this.]
[Update: just for fun, I dropped this map into Google Earth, and it’s very well-scaled. There’s some distortion around the south edge, most likely to get everything to fit, but most of the map overlays so well that you can easily locate individual shops.
Also, someone has made a set of Google Maps pushpins that covers some of the highlights of Akihabara in English. There are also two decent ones (1, 2) if you can read some Japanese. The first one is a collection of maid cafes, the other is more general.]