I just received my new Tom Bihn Ristretto bag for the Macbook Air. I purchased an STM Scout from Amazon shortly after I bought my MBA in April. The Scout is a fantastic bag for carrying both the MBA and the iPad. My only problem with the STM bag is the lack of space for extras like pens, earphones, etc.
I purchased a Tom Bihn Ristretto for my iPad last year and I really love it. When I am only taking my iPad somewhere, I use the Ristretto for iPad. After purchasing the MBA, though, I needed a solution for taking both the MBA and iPad together. The STM bag was a good first choice - I needed something there and then and the next production run for the new Ristretto for MBA would not be available until mid-May. In addition, the STM from Amazon (at that time) was only $35.
Another reason for needing a bag to accomodate both the MBA and iPad is that I am traveling next week for WWDC in San Franscisco and I want a good bag for carrying both devices around.
Last week I ordered the Ristretto for MBA from Tom Bihn and had it shipped 2nd Day Air via UPS. It arrived this past Tuesday and so far, I really love the bag. It holds both the MBA and the iPad with plenty of room for a small Tom Bihn bag for carrying cables, earphones, etc. In addition, there are a number of extra pockets and space for other accessories such as pens, clothes, etc. I chose the same interior color which is an Cayene and the exterior is Olive (the Ristretto for iPad is Cocoa on the outside). I ordered it with the standard strap since I had an abosolute strap already with my other Ristretto bag which I swapped with the new bag.
These Ristretto bags are probably a "buy once" purchase since they are built to last forever. I really look forward to using the new Ristretto. I will keep the STM Scout as a backup or for my wife to use when she needs a carry bag for her MBA.