Originally Posted by
no1mad
*cough*
-Messenger bags that swing around are not true mess bags. They are shoulder bags that lack the stability strap.
-Seat post rack will not support too much weight.
-"Backpacks sit up too high/too small" have never (probably) seen a
Banjo Brothers Backpack. They have some looong straps compared to other packs that I have owned over the years.
@OP- depending on your budget, you might want to check out Carradice saddlebags that attach to your saddle. Also, if you aren't too leary of buying from e-tailers, look into what the Europeans have to offer. Germany's Rixen and Kaul has some nifty products.
I have to agree with this advice too. Having used a bunch of different messenger bags (Timbuk2, Crumpler, R.E.load, Baileyworks, Chrome in that order of preference and fit) and backpacks, there is no ideal bag that works for me.
Depending on the weather and type of load I switch between a Chrome Metro (cool/warm weather) and a Banjo Bros backpack (cooler/cold weather).
My favorite carrying method is to put stuff in a small ultralight backpack ( I use an REI Flash 18) which goes into my Carradice saddlebag. Keeps my back bag-free, let's me take my stuff with me when I am off the bike, and gives me extra carrying capacity if I need it.
If you are not carrying that much, then you could try a small backpack (20L or less). Both the Metro and the Banjo Bros bags might be overkill. Deuter and Camelbak offer some nice small cycling specific packs.