MapTools comes bundled with a variety of nice set-piece tile graphics for things like walls, stone floors, furniture, torches, and so on. My approach is to sketch the rough map on graph paper, scan or photograph the sketch to a JPEG, and then use it as the blueprint for the rest of the map.
MapTools also works as a virtual tabletop. So once a map is ready, I set up my PC as a server, and keep a small laptop behind the screen with the DM view. Another player connects his laptop to a projector and displays the players-only view. Our remote player(s) dial in and see the same map and tokens as everyone else.
You can install several "frameworks" or collections of scripts which will let you import/export DDI power cards, monsters, and character sheets. I don't think I would use a framework if all of my players were at the table, but because one of my players Skypes in, it is incredibly nice for him to be able to roll his attacks with a few clicks instead of having to type "/roll 1d20+8" over and over for a burst attack. A third-party utility called MaPnakotic brings support for iPad and iPhone devices, which is nice when my players want to pass around an iPad to look at the nooks and crannies of a map.
I still use MasterPlan for encounter balancing and plot threads, but for mapping, nothing beats the flexibility of MapTools.