Besides the appeal of city life (Miami and Atlanta do NOT qualify, IMO), I would agree with the above. The movers and shakers might want to be in the thick of things in major firms doing major transaction work.
From a purely practical standpoint, though, there are probably more plentiful jobs in a primary market vs a secondary market. I would speculate that while your second scenario of 140k in a secondary market would make more financial sense, that sort of opportunity is few and far between (even more so than the 160k in a large market).
There may be more total jobs in a primary market, but there's also likely a good bit more competition for those jobs, especially the top-notch ones, than there will be in the secondary markets. Since so many T14 grads gun for the big markets, if you have a T14 degree and aim for a secondary market you'll likely get a pretty darn good job since you're competing mainly against regional schools.
There have been some rumblings that T14-ers have been having some difficulty in secondary markets because they are viewed as a flight-risk ITE (i.e. if they could get New York, they would leave that market in a second). If you go to a top school and want a secondary market, make sure to work there during both summers, otherwise employers may think you do not want to stay long term and will bolt when NYC comes calling.
BigLaw in secondary markets also tends to be on a much different scale than in large markets, so keep that in mind as well. There just aren't the same number of position to be had and SA's are hired minimally (only a couple a summer and they usually hire 1-2 local kids out of 3 total positions; not many which is why most T2's and lower T1's have a very low BigLaw %). It also depends on what secondary market you are aiming for. Boston will be different from Seattle, which is different from Miami, which is different from Denver, Nashville, Atlanta, Charlotte.... (etc., etc., etc.). Some legal markets are larger than other markets; some firms prefer local graduates more than others; some markets are doing worse/better in this economy, etc.
If you have your heart set on BigLaw, you want the big markets. And if you want the big markets, you want T14. Although ITE, if you just want a job period, you probably want T14 anyway....
Note: I have crappy numbers and am not getting close to T14. But I'm aware of my fate.