Hello RDW,
Blasewitz is a good part of Dresden. However, the best parts of the city is to the north of the river. (Neustadt, Loschwitz etc)
Nevertheless, if you get hold of an apartment overlooking the river/
Castle Eckberg, that would be awesome. Ofcourse, the noise levels could be a touch high, but the superb views plus the proximity to the Bicycle path along the River Elbe will more than make up for the noise.
Supermarkets are aplenty all over Dresden..not sure about DVD rentals, but would expect a few in that area. Close to Wittenberger strasse is a
cinema hall.
There isn't a sub-way system in DD and actually, there is no need for one. The Tram and bus system is fantastic and if you throw a bicycle into the mix, you can easily get around the city. I checked on the
Deutsche Bahn website and there is a tram station, which is a few minutes walk from the wittenbergerstr stop. Depending on where exactly you will be based on that long street, you might need an additional bus ride to get to the tram station
If you are an enthusiastic/frequent biker, biking along the Elbe upto the
Sachsische Schweiz will be extremely tempting and worth your while.
Have fun,
Sudhi