"1) Is there a general consensus as to whether or not it's better to live on the orange or yellow line?
2) Are there any townhouses/rowhouses/duplexes available that are reasonably close to a metro station?
3) Are we destined to end up living in an apartment comples?
4)Is it feasible to try and ride a bus to a metro station, or will that just result in a 45+ minute commute? Or maybe just to ride a bus all the way?"
Hey, I'm an undergrad in D.C. right now, with a lot of recently graduated friends that live in and around DC. I'd say you should def. look around Arlington, near one of the metros, like rosslyn, clarendon, ballston, etc. which are orange line, or pentagon city which is blue/yellow. A lot of grad students/young professionals live in these neighborhoods in either apartments, or condos. They usually range in price with how far you are to the metro station.
In DC you could look at U St./Adam's Morgan or around Union Station. But these places aren't usually as nice as No. Virginia, and the most options are usually townhouses you'd share with other people.
The metro is convenient enough that if you're near a station, it doesn't matter which line it is. Although I think the orange/blue line hits a lot more hot spots in DC than yellow.
A lot of people do take a bus/metro combo to get places, which is usually fine, but I will say that buses can be really SLOW during rush hour. A lot of people ride bikes around. Personally I walk a lot, especially during non-peak times when the buses/metro trains are less frequent.
If you haven't seen it already, this is the metro website: http://www.wmata.com/
The trip planner part of it is really great.
This was probably inarticulate, but I could give more info if you have any other questions.