Okay, I can't quit obsessing over purchasing a messenger bag. I'm going with a Chrome and am debating between the Mini and the Citizen (small and medium, 1000 and 1400 cuin respectively).
I will be doing three different things with this bag. 1) I commute to work twice a week and need to pack lunch, shoes and clothes, a notebook or two, wallet-type stuff, a little bag of make-up. 2) I will ride to school where I may need to pack a laptop, a textbook or two, a couple of notebooks and such and 3) For weekend fun rides I'll need to pack water and food, maybe a towel to sit on, a book or two, a notebook...
11 years ago I debated about which Timbuk bag to get. I ended up getting the tag junkie which, at the time, was their largest bag. Not a mistake. You'd be surprised how often that extra volume comes in handy when you're commuting.
I agree you need the big one, but are you sure a messenger bag is the answer? Sounds like you'll be carrying a fair-sized load pretty consistently, and at least for me, a messenger bag dangling from my shoulder is a PITA on any ride longer than half an hour, max. Even the good ones (I have a Patagonia) don't ride as securely as I'd like, the shape isn't ideal for clothing or bulky things, and they're sweaty in hot weather.
Most of the time I use a Carradice Longflap seat bag, sometimes with a Rivendell Baggins Hobo Bag on the handlebars. Here's a link to Carradice: http://www.wallbike.com/carradice/ca...addlebags.html,
Riv doesn't have the Hobo Bags anymore, but this is similar: http://www.rivbike.com/webalog/baggage_racks/20128.html
when did patagonia become a bike messenger bag maker? ... only kidding ... the chrome bags will comfortable when you ride, no question about it ... that is, after all, the one and only reason they were made.
get the bigger one. I'd even say go up to the metropolis (makes stopping by the grocery on the way home a little easier)