Okay, here's an idea, for someone with a lot of time to try.
Take a map of DC, showing the METRO stops.
Get a compass (not the N/S kind, but the 'draw a circle' kind._
Draw a series of shaded circles around each METRO Stop, at 1/4 mile, 1.2 mile, 1mile, 2 miles, etc. (These may overlap)
Historically, Areas with METRO access have best appreciated.
where the shaded circles overlap, you'll have the most appreciation. Where there is no shading, or little shading; no appreciation.
The trouble with this is, that the METRO's have been around a while. Most of the appreciation due to METRO's has already happened.
BUT, its a good technique to look at other factors that might 'apprceiate' an area .(sorry, just turned appreciate into a verb!)
Try similar for:
Streetcar (not just the one coming soon, but the larger plans DC has, they're on-line.
Major developments planned for Federal or Private groups, such as Malls, etc.
Anything else, you think are assets for homeowners, inlcuding, new interstate access, etc.
So, No, I haven't answered your question, but I have given you some tools to answer them yourself!