Today I bought a travel guide for myself. It's called Not For Tourists Guide - Washington DC edition (official website available here). Apparently they are also making other editions including Boston, Chicago, and Los Angeles. Unlike mainstream guide, this one is created for newcomers to the city, those intending to live for extended period. Therefore not only you can find the usual recreational destinations such as the Smithsonian complexes, the Zoo, and historical sites in DC, but also the more mundane but essential spots for residents such as post offices, banks, pharmacies, and grocery stores.
The book's content is dedicated in the most part to providing readers with series of maps, 46 to be exact, and several sub-maps. So, instead of telling stories behind such-and-such place, the book will show you the map of the place so you can figure out yourself how to get there and what stuff is available in the surrounding neighborhood. The maps are very reader-friendly and interconnected with one another. So, instead of carrying a huge map everywhere (and being obviously tourist-acting), I just need to carry the book and stroll along.
In the following month during my stay, the book would provide tremendous help in getting me up to speed with DC's public transportation routes, key neighborhoods, street names, and essential venues (banks, post offices, etc). The book is still useful every now and then, even when I already familiarized yourself with key areas important to me.
I highly recommend this book for those of you who will move to DC or just recently moved here. I haven't read editions for the other cities, but assuming that they will all be similar, then you can get yourself a copy depending your destination cities.