Macbook Air Messenger Bag

I am looking for a messenger bag for my new Macbook Air (13"). Any suggestions?
Thanks.

What is your budget?
What material do you like?
Try timbuk2
Shop for a Messenger Bag, Backpack, Laptop Sleeve, Luggage or Design Your Own Custom Bag Made In the Mission District, San Francisco - Timbuk2 Bags
Crumpler
Crumpler | Backpacks, Camera Bags, Messenger Bags & Laptop Bags
Rickshaw
Rickshaw Bagworks | Shop urban messenger bags, iPad sleeves, laptop sleeves, backpacks or customize your own bag all made in the Dogpatch, San Francisco
Tom Bihn
Travel bags, laptop bags, and backbacks. The best materials and innovative construction since 1972 - TomBihn.com
Waterfield
Need a case or bag for your laptop, tablet, mobile device, smartphone, or gadget? We've got you covered - WaterField Design - Made in USA - Made in SF
My current bag is saddleback - but it is heavy and expensive. That being said it is never going to fall apart.
Saddleback Leather Co.

+1 to Saddleback Leather. I carry my MB Pro 15" in one of their Thin Briefcases and have their MacBook Air sleeves for both my 11" and 13" Airs. I also have one of their medium Gadget Sleeves for my iPad mini. Their warranty is 100 years and you will understand why when you see their workmanship.

Thanks! You guys have been very helpful.

How about coach? I have 2 of their messenger bags and they are great.
Designers Mens Business Bags, Travel Bags, and Tote Bags from Coach

I love Saddleback Leather, I have one of their wallets.

My computer back is a Timbuk2 bag. Lifetime warranty if you get one of the custom made in San Franciso versions.