I stayed at The George: A Kimpton Hotel(http://www.hotelgeorge.com/) This place is affordable, nice and clean. And on a plus, it is fairly close to Union Station. To go to attractions, just ride a trolley, it won't take too long, and you might even learn some stuff.
I've stayed at the Hyatt Regency on Capitol Hill several times. Not super pricey, good room service, several restaurants nearby, 4 blocks from Union Station, super close to Metro station, a nice secure pool for the kiddos, and the most comfortable beds I've ever slept in in my life. Highly recommended.
I stayed at the Tyson's Corner Marriott when I went to the Rally to Restore Sanity and/or Fear. And I would recommend the place on price alone. I think it was 80 bucks a night (But I'm sure depending on when you go it could be a lot more expensive) and maybe a mile from the subway station which we took to get into DC. There is a million things to do in the city but I would recommend doing the Skyline Drive in Virginia. I don't know what it looks like at this time of year but when my wife and I drove through in the fall it was absolutely beautiful. And after the hustle and bustle of our first couple days in DC getting out there was a welcome breath of fresh air (both figuratively and literally).
I'm going in a few months and will be staying at the Donavan at Thomas Circle. Has anyone ever stayed there?
