I know you're looking for something smaller, but depending on your job a messenger bag could be just the thing.

My best bet is either a backpack or messenger bag. Now that I have a laptop as part of my EDC, a messenger bag with padded laptop section is ideal-- and leaves plenty of room to carry my contingency gear.

When I'm taking classes, I fit in (though as an older student / professional). When I'm working in IT, I come off as a slightly geeky professional. Either way, I fit in, look professional, have plenty of freedom of movement, and can carry the gear I need.

The trick is to avoid over-packing with all that space I have. A half-empty bag is NOT a problem.

Third on the Fatboy. I have a Jumbo and it's not huge. The standard size should be about the size you're looking for. Originally I used a Thermite, but wanted something larget - and the Nalgene spot on the Jumbo was a big selling point for me - as well as the ability to add other pouches.

I prefer the Land's End Canvas Briefcase for my EDC and I have a small Eagle Creek carry bag for my survival stuff inside the land's end bag. You might want to look at this new Blackhawk Battle Bag [Messenger Bag] they just came out with:
http://www.blackhawk.com/product_detail.asp?product_id=4236&d=

I think you should refer to whatever bag you get as a messenger bag rather than a 'man purse' -- that sounds so much better IMHO <img src="/images/graemlins/cool.gif" alt="" />

you forgot a name - an old, respected REAL name

A "Possibles bag"

at one time, all hunters/woodsmen carried a "possibles" bag

Or possibly a bag of tricks

Or a bag of holding. Although that might be my inner geek showing through.

I am partial to the term shoulder pack. I always figured if a pack worn on the back was a backpack, then a pack worn on the shoulder must be a shoulder pack <img src="/images/graemlins/smile.gif" alt="" />.

Pete

I personally think that you may find it more convient to get a day pack for a number of reasons: More space and two shoulder straps. You may need to walk/evacuate longer distances, and having it over your shoulders on your back may be more confortable. Plus, it looks cooler. <img src="/images/graemlins/smile.gif" alt="" />

I purchased a North Face Neutron 32 backpack. It has 1 main compartment, with another exclusively for a 70oz Nalgene pouch. There is also an organization area for pens, pencils, keys, etc. Its gets full pretty fast. I have rain gear (jacket and pants, they both "store" into their own left pocket, pretty sweet), first aid kit, multitool, hat, water, snack, mini flashlight, glowstick, fox 40 whistle and lanyard, sunscreen, towel, water and spare set of glasses. On days I go to the gym, it gets real full with just my clothes. The sneakers are too big to fit in it, but in a pinch, I could attach them to the outside of the bag. Depending on where I'm going and what I'm doing, I can still add a hygeine bag (toothpaste, toothbrush, mouthwash, dental floss, razor, shaving cream, shampoo, comb, deodarant (currently a stick, need spray, doesn't hold up to the heat very well)), amateur radio HT, spare keys, and spare cell phone battery pack.

The only thing that I could really use, and probably could attach to the bottom of the bag, is a small tent, and perhaps a tiny pillow. With clothes and a towel, that may not be necessary.

It also features some "cinching" straps on the outside to bring everything closer to your back. Oh, it also has a place for a bicycle helmet too.

The North Face Neutron 32

While I'm sure the Blackhawk bag is top quality, $100 is more money than I want to spend. I got a reasonably good messenger bag from the Gap for $10.

it's more than I would spend too, but thought I would throw the link out there since it is brand new-- I paid $25 for my lands end briefcase years ago and about $15 for the eagle creek smaller bag I carry in it

I fourth the fatboy it sounds about perfict for what you want. It is much smaller in person. The main compartment holds two .5L bottles of water with some room to spare. hope this helps. <img src="/images/graemlins/smile.gif" alt="" />