Yes, the Marriott is literally right there at IAD on Aviation Dr.(?) and it also has a free shuttle and Concierge floor and other decent facilities such as gym, pool etc, as I recall.
The Suites is also only about 2-3 miles away with a free shuttle too, I guess.
FWIW, the nicest property here in the area, IMHO, is the Marriott Westfields - but it's a few miles further out from IAD.
Corrected to IAD, as directed below. I got CO on the brain and I was writing a letter to Houston today!

Thanks!
[This message has been edited by doc (edited 01-16-2002).]