I saw the Incase in the discount stores for 75% off. I didn't like the feel of them. I did some research here and what stood out for me was the Tucano Sleeve. I'm a person who like for a gadget or material to feel nice to touch. It has to feel expensive, nice quality, and without paying a lot for it.
So, I searched and found the Tucano Second Skin for $25. It's a tough neoprene that is definitely weatherproof. They come with a protective covering over the zipper parts so that it doesn't scratch your MBP. I've had mine for about two years and it still looks new. It has that new smell too. They even have a cable pouch for it.
Buy from here w/free shipping and no tax.
http://www.adorama.com/SearchSite/Default.aspx?searchinfo=tucano second skin
mine shown here
http://www.flickr.com/photos/77634324@N00/4231962066/in/set-72157600178258293
I know you want a carrying case but imo those aren't really ideal. I mean I'd rather carry in a sleeve then place in a bag that also well padded. I carry mine in a Timbuk2 Blogger bag. Its smaller and has tons of compartments. Timbuk2 makes a laptop bag.
http://www.timbuk2.com/tb2/products/cubicle-laptop-messenger
or their laptop case
http://www.timbuk2.com/tb2/products/control-laptop-case
I like Timbuk2 because their stuff is very rugged, durable, water resistant, the whole nine. Great product. If you want to check out the quality, try Best Buy. Apple stores use to carry them but no more

You can buy from their site.