Ben Minkoff - Nicky Wazwear Messenger | $395
Now you don't have to drop 400-big ones on your first messenger bag, but you should look for similar qualities. This one from Ben Minkoff (you can find this at Bloomingdales or Endless.com if you need) is classic. Good neutral colors, a few extra pockets, and the strap details are perfect especially if you are a beginner to the fashion world.The key is to know when to use a messenger back (probably 4 days a week) and when to use a weekender bag (gym days, long days that require change of clothes etc) like this one:
Fossil - Decker Duffle | $278
Personally, I like the darker brown on the bottom right but the choice is yours. The point is to know that you need BOTH these bags to wear them properly. An oversized messenger will bother you in everyday use, and an over-stuffed messenger just looks childish. It's ok to need back up supplies, just remember to use the right bag bringing them.
Happy travels everyone, and swag on.