I have to carry around pads And lots of meeting minutes for work, so I carry it in the Hard Graft 2unfold bag. I first got the bag for carrying my macbook air around, and I have to say it fits both nicely. Although that said, I get teased a lot for carrying around a European man pures as I work in construction. But it doesn't bother me at all, because I love the bag so much! Not to mention every day it gets a little more worn, and a little more "my bag".
http://shop.hardgraft.com/bags/2unfold-laptop-bag-grey
Targus 360 case...Then I throw it into a Timbuk2 XS (if I am just going out for the day), or my larger Timbuk2 if I am travelling.
Then again, sometimes it just gets thrown in my gym bag (of course, protected in the Targus case, along with a great velveteen soft pouch drawstring bag I purchased off of Ebay. I bought something like 20 of these bags. They are great for the iPad, as well as any cords, adapters, etc.)
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=170487309473&ssPageName=STRK:MEWNX:IT
Hard Graft is awesome. I used my first generation Tilt iPad case to build my own smart cover with all the same magnets/features of Apple's Smart Cover.
I also use their 3FOLD bag as a messenger/duffel and a Qwstion Backpack when I need a backpack.
I had an incase neoprene sleeve, but returned it for the more professional looking Sena Executive Sleeve. It works great with the ipad smartcover and it has enough room under the flap to stick a stylus. Its leather and has held up very well over the past 6 weeks.
http://www.senacases.com/apple/ipad-2-cases/executive-cases/#
I was looking at getting the 3FOLD gab when I bought the 2unfold. They weren't in stock at that time though, and I sometimes wish my bas was just a little bigger. I also had bought the new tilt ipad2 case, but ended up selling it, as I didn't like how much bigger it made my ipad. So now I have a ICarbons skin on it instead.
BTW thanks for the link on that backpack. It will be going on my to-buy list for sure! It looks perfect.