I have a Chrome Metropolis. I prefer backpacks now. It is much easier to get in a messenger bag (especially while riding). A backpack is just much more comfortable though. Pac Designs Bags are supposedly the cat's pajamas.
I use a laptop sleeve from Waterfield Designs. I've also read a lot of positive things about the Tom Bihn Brain Cell. You can get sleeves for much cheaper, but they probably won't offer as much protection and quality.