If you are hard on your bags then I suggest something by Longchamp. They have some great leather ones with zip closures, are classic, lightweight, sturdy and well-priced.
I have the LM tote and use it for when I have lots to carry with me. It's super light and looks good even with a ton of books/papers inside
Kate Moss also just did a few bags with them and they look very interesting.
There is also an option for designing your own Le Cabas.
Coach Kristin leather large tote in black/silver $598 on Coach.com
plus, Coach is having a PCE right now so, if you could find someone with an extra PCE card, you could get 25% off.
There are some PCE cards listed on ebay right now, just do a search on ebay for 25% off Coach.
PS: 2nd pic is of the same bag but, in chalk/silver. They don't have the modeling pic on the website of the black.