So I want to get a timbuk2 or a Crumpler bag but I'm thinking of getting just the messenger bag and not the specific laptop messenger bags. I need a good (protective) sleeve that will fit over the MBP with the hardshell. Any suggestions? By the way, I'm getting the non laptop bags because I won't be taking my laptop to class a lot but I'll be using my bag for everything. And Crumpler's laptop bags are different than their regular messengers.