@OP: It really depends on what you're trying to get into. I'm assuming you're going into something related (IA, tax, senior acct, etc), in which case the longer you stay, GENERALLY the better opportunities you can get. However, this varies a LOT based on how well you network and interview.
I personally left just before senior promotion in August, and got a significant raise to join an IA group at a Fortune 10. It was a need and skills fit (new IA group specializing in Finance), so that's the reason my offer was better (80K base from 54K as 2nd yr audit staff). I'm in a mid sized city now (cost of living is probably comparable to Charlotte/Atlanta.
However, I was looking at opportunities that were commonly in the range of 65-75, so 80 was on the upper end of what I expected (hence, why I quit and left immediately). I did come in as a senior auditor/consultant, not staff, so that's definitely part of it. I'm sure staff are getting paid 10-15k less here (very few college hires, mostly experienced.. at least 1 yr ,usually more).
Agree with above posters. Leaving before senior is not worth it, IF you cannot network/interview your way into a promotion (not just a lateral move as a staff accountant/tax analyst/internal auditor/etc).
Of course, these considerations mostly matter depending on your own career aspirations. THat is another conversation entirely.
To answer, my hours now range from 40-55. Avg I would estimate is 47 if I had to pick a number. Stress is still there, but no job is stress free. Of course, I have more responsibility now than I did as a Staff 2 at Big 4, so the two aren't directly comparable.