Have you considered a good backpack?

I've had all kinds of messenger bags over the years. I've given them all away except for my Chrome Metropolis. I only use the Metropolis when I need to carry lots of stuff. I use backpacks for everything else...especially if my laptop is involved.

My suggestion: Incase backpack or other nice backpack.

http://goincase.com/products/style/backpack

I've had my Incase backpack (can't recall the model name) for over 4 years and it looks new. The quality is top notch.