Hmm, the gun situation in DC is still pretty bad. However, it isn't like Chicago (anymore) and may be a tad better than NYC.
I normally agree that more gun people in an anti-gun area is usually better. Work from within, fight new gun restrictions, and try to roll back current restrictions. Moderating the bad states is good for all of us. However, it can be like banging your head against a wall and you will tire out. DC is worse, everything good that has happened there for guns has been by court order with the vast majority of the people of DC being dragged along kicking and screaming.
On the other hand, if it is a temporary move, I can see it. DC (like NYC) is a great city for single young professionals. A lot of culture (museums, opportunities for the opera/theater, music), entertainment, singles, jobs, and great nightlife and if you live there you can be in the thick of it. Guns are just one part of our lives and lifestyles.
For your purposes I'd stay away however. To buy affordably you'll probably be no closer to where you want to be for entertainment and nightlife than if you move to PG, Montgomery County or NOVA within or near the beltway. To buy in a desirable neighborhood it is quite expensive, the MD suburbs will probably be cheaper and much of NOVA may be. To stay long term (which if you are buying I assume is the plan), I'd much rather be in the 'burbs once marriage and kids come, even ignoring gun laws- safer, bigger yards, more accessible open space/parks, and much better schools.
You say you live a 10min walk from DC in VA, and then put out the strawman of living in the city v. living 90min out. If you live within the beltway you will be near DC and you'll have the metro near your home- you may be able to get to where you want to be quicker than many places within DC. DC itself, if in a desirable area isn't any cheaper than the 'burbs (there is reasonable housing in NOVA and definitely in MD- "reasonable" being comparative, I doubt someone living in 90% of the country would consider anything in the DC area to be priced reasonably). Heck, even a few miles out of the beltway you will be near the city and the metro, and many of these areas have grown into little cities themselves with decent nightlife and most of what you'll want most of the time anyway (Arlington, Alexandria, Bethesda, Rockville or Silver Spring for instance). The MD 'burbs aren't good on guns, but MD is much better than DC, and the prices will be much better than DC for comparable property (and we have our "up and coming" neighborhoods as well).
If you do it, keep in mind the "PC" nature of the area. I know in Baltimore you pretty much will be charged in any home defense shooting, I assume DC is no better. Keep your defensive weapons as PC as possible since your jury will come from the anti-gun local population. You don't want them to be shown your "Rambo wannabe" or "military style" weapons- nothing with the word "tactical", try to stay with wood stocked rifles/carbines (lever rifles are probably best) or wood stocked pump shotguns (stay away from "military style" "evil black rifles and shotguns" so no plastic/polymer). Any pistol will probably be a big hurdle to overcome (though they may be an indispensable home defense addition) so stay away from anything with the word "tactical" or any stick on devices (don't use the utility rail) but I don't know if a revolver over an auto will do you much good or not (I do still use more revolvers than autos for HD purposes).