Arlington and Alexandria are pretty nice, I actually live in Falls Church, not DC. DC is a good town, around Georgetown, Cathedral Hights, Dupont Circle (actually, thats questionable, it was a fun place to go out in). I'll definately miss the museums, (I've gone to very few unfortunately, will have to come back as a tourist to see them).
I'll most certainly miss Eastern Market and the Fish Market, both in not the best parts of town, but Eastern Market has wonderful jewelry and artwork, and is a great Sunday "after liturgy" place to go. I always spent WAY too much money there. The Fish Market has THE BEST crabcakes and fried calamari I've ever had.
Also, kayaking on the Potomac is one of the top things I recommend for any DC visitor.
Also, the surrounding area is great, especially west of DC, and of course West Virgina is a must see, and I'll most certainly miss hicking around Harpers Ferry.
I've made a lot of friends, and even have a godson here, so I will definately be back to visit.
But, it is time to go. :-D