MELT Gourmet Cheeseburgers is a local joint in Leesburg, VA
Ranked Top 10 Burgers in the USA from a number of different websites.
Locally sourced ground meat blend for the burgers, homemade buns daily, lots of great burger combinations, fries, adult milkshakes, etc - blows me away every time we go.
For burger chains - BGR, The Counter, and Fosters Grille are usually safe bets for me. I've never been a big fan of Five Guys (and the original location is in my hometown...), and it always makes me feel like I need a shower afterwards due to how greasy everything is there.