I have a timbuk2 sleeve for my TiBook in a messenger bag that i totally love. I take it everywhere! from coffee shops to random places and its been great. I have no complaints about it what so ever. The quality is top notch and theres a good solid padding on it. Some say its a bit pricey for the sleeve but i figure i spent close to $3000 at the time with all my "ever so important" upgrades, i can spend a few dollars more.
I spent weeks looking for the perfect bag and been routed over and over again to eBags, searched high and low and couldnt find anything else better.
anyway play with their site! i believe its timbuk2.com
. you can fully customize your bag, and if you think about it... when do you really buy a new bag or backpack? so spend the money!!