I vote for the Hamptons Large Carryall in leather, 11332, because it is such an understated and classy bag and can be casual or dressy. The mahogany color goes with brown or black and will be really versatile.
I have this bag and I consider it one of my very favorites...just gorgeous!
While the hamptons carryall in all sizes is a lovely bag, as are satchels, keep in mind we are not just recommending something for a working woman, we are recommending something for a busy mommy, and I find those bags to be a PITA for me...and I don't even have kids yet.
The ergo hobos are the best bet I think because they do NOT come off the shoulder, very low maintenance and look classy OR casual if you want them to.
I vote the large belted hobo in black. You really can't go wrong and she will get many years of use out of it as well as many compliments. The leather is sturdy and beautiful and the belted detail adds something special.
The hamptons carryall is much harder to maintain in terms of keeping it on your shoulder.
The chelsea turnlock pictured above doesn't present me with any issues...I have the wristlet and it's very easy to turn it and open, better than a zipper. The ergo hobo has a zipper but it's big so it doesn't really have any problems there.
I have the Hamptons Signature Carryall but I am thinking in exchange it because it is not so much my style. It's a large one, very roomy. I am not working so I just need it for when I go out with my baby but if you say that she is working it will be perfect, specially if she work in a office or something like that...