I've always liked the Union Grill and have been coming here since I moved to the city in 2003. It's traditional American fare and by no means will the menu blow you away with creativity or culinary ingenuity, but it does serve satisfying hearty meals at a reasonable price. I've went here with friends, I've went here with dates, I've been here by myself, so it's the kind of casual place that suits whatever you might be looking for.
The menu changes occasionally depending on the time of the year, but I usually stick to the basics like the Reuben or the fish tacos. I've had the "famous" Turkey Devonshire which is good, but very heavy which makes it sort of overwhelming.
If you don't feel like waiting for a table or are by yourself take a seat at the bar and order your food there. It's a nice little restaurant bar with a nice beer and liquor selection which also has some nice happy hour specials.