Not sure if you guys run into this problem but always have my pockets full with crap and have stuff flying all over the car when I'm going from auction to auction all day long. I picked up one of these bags a while back and love it.
Smaller than a backpack. I also like that it can hang on your hip instead of back so can keep money in there and know it won't get snatched. I keep gloves, hat, flashlight, mp3 player, several locks and keys, smokes, waterbottle, phone and maybe a magazine for when sitting around waiting for auctions.
It's actually meant to be a conceal carry bag and has a concealed pocket with velcro for a velcro holster to keep all that cash safe as well if your in a CCW state. Also you feel like less of a woman carring a gun bag than a man purse lol.
Anyhow, I really like it, it keeps me organized, is conveneint and keeps me from losing things.
I don't sell these bags nor do I make any kickback from them so nothing to gain, just giving some helpful advice. I used to be an aamazon affiliate so made a whole 3% but they cancelled the program in my state so make nothing. The bags are cheap too you can pick one up for about $23 on ebay free shipping too. Its a knock off of the maxpedition bag but same quality. You can also buy all types of extra clips and things that can attach to the bag.
I did a review on my site as well as ebay if your interested in taking a look
http://rulesforrebels.blogspot.com/2010/12/product-review-of-utg-messenger-bag-by.html