Maps come in handy, when you are looking for a metro station, some street, some address or a party location. I am using different maps for Moscow and often I have to combine them, to find what I am looking for. To make it easier for you, I added Google Maps to each interesting location based article, so you can find it easily yourself. For all other tasks just use these:

Yandex
http://maps.yandex.ru
In Russian, but very detailed down to the apartments and yards between the streets (not like Google). The map also allows you to save it with a marker. You can then export it into your phone or camera (which is a trick I have learned from my friend Michael Pütz) and take it with you, whereever you go. You can also send the link to friends explaining them where you live or where to go. The map has a Russian street index, shows the weather in certain city areas and you can even find traffic information on Yandex. They also show markers (optional) for hotels and other useful and less useful (sponsors) locations.

EuroAve.
http://www.euroave.com/maps/frame1.php?xcity=moscow
The map is in English, but the functions are outdated. It simply a scan of a paper map and you cannot move it, like in Google or Yandex. Nevertheless it has one feature that comes in handy. It has a street index writtin in latin characters and even though some translations are horrible, you can usually find the street on the map, along with the next metro station and then look for it on another more detailed and easy to use map like Yandex.

Metro Map by Hotels Moscow
http://www.hotels-moscow.ru/metro.html
Its the best quality and largest metro map I found on the net. When I arrived in Moscow they still only had cyrillic metro maps and this english one was very useful. I also downloaded it on my phone and now I have it with me anywhere I go.

Google
Well, it may not be the most detailed one, but it has some nice functions. You can use the maps on this site and zoom in and out to find the location and see how to get there, from where you live or stay. Google has also a nice “Sattelite” functions, which actually shows you the street as a photograph from above. Beat this!

Here is the famous Bolshoi Theatre for example. Its being renovated and closed, but the nearby new house of the Bolshoi (just on the left) is open and they make most of the performances on the so called “new stage now”. Try this… click on “Satellit” and then move the map with your mouse left and right. Right! You can drag it (left, right, up, down) and get an arial view of Moscow with photos.