I invested in a Crumpler Weebee a year ago, its mostly used to tote around my powerbook and associated parts. I've never had a major issue with it, no split seams or damage, even after packing it full and streching it further than it should.

Over the last few weeks my better half has been looking for a new messenger bag and I did point her to the way of a Crumpler. Over here (in the UK) Crumplers are in the ?100-150 price range for their decent size ones, which is a little too expensive. What you have to remember is that this bag will last you a long time.