I fly enough that I get lounge access with my airline status. Seeing as how I've had it for free for a few years it would be a lot harder to assign a monetary value.
If you don't usually have access, the value of the lounge would be significantly higher.
I value the ability to find a place to work (even when the lounge is busy I can find some table space), the cleaner washrooms than the rest of the airport, and the ease. If I wanted to eat somewhere else I could, but sometimes I just don't want to deal with it.