Geography can be important, but it's not the only factor in quality of life. Sure, if you like big cities, you shouldn't look for a job in Podunk, and if you're allergic to people, steer clear of Megaopolis. Choose one that matches your own. This can be difficult for a law student, but not impossible. Pay attention, especially in your summer clerkships.
Interviewees obviously have a fine line to walk.
Usually, mid-level associates are the best source of information, but be careful there, too. After you been practicing a while, you'll develop these contacts, and learn about various firms. Also, it's easy to generalize about areas. There are cool firms in Boston, and there are stuffy firms in Reno. A statistical average is of little importance when you're in a single, solitary, stationary, non-statistical office.