Location, Location, Location!

In a little turn of events I've decided to talk about where my stories take place. I know a number of my writerly friends will often center their stories on locations that they know well or have lived in. I'd say about half of them do that. Then there are those that choose to set their stories in completely foreign locales. Some of them are complete fiction while others use real cities. As for myself I go back and forth between these two solutions.

To tell the truth, location for my modern day stories is one of my pitfalls. I suppose my biggest issue is that I'm never sure how specific or vague to be. I understand that it's a fine line between too little and too much information and I've improved over time, to be sure. My best solution thus far has been to mix the reality with the fiction. I'll pick a location or city that I think might work than alter it to suit my needs. The result is  the flavor of a specific locale but with proper distances and place relations that my plot calls for. If you look hard enough there are usually tell tale signs of which city I've pilfered from though.

Fantasy is much easier to a certain extent and more difficult in others. When creating a fantasy world (or a map which is where I usually start) it's hard for me to leave the unknown...well unknown. I have maps for cities, buildings, villages, almost everything. At times feel more like a cartographer than an author. I'm a visual sort of person so I suppose it can't be helped! The only problem I really have is when my OCD kicks in which is almost all the time, hence the multitudes of maps. Whatever works for me right?

What are some of your location secrets?