In this case, the ssd is more about speed than savings. If you want faster, and that thin form factor, you pay for the solid state drives. Early adopters pay a tax. The point of the macbook air is for road warriors and executives, etc, who don't want to carry a big laptop bag. It's not something I'm more than casually interested in, but that's mostly because I don't fly 500,000 miles a year anymore.
As to the mac pro, sure it'd be nice, but I don't really tax my mac mini as it is. I could rip movies a little faster with the mac pro, but that's not a huge deal to me. I'll probably never buy another fast desktop. I'm not at all impressed with fast desktop computers, much in the same way formula one drivers probably aren't impressed by the subaru wrx.
This isn't a computer for geeks, really. There are lots of those out there. This does have some really nice innovations tho, especially the multitouch touchpad and the ssd drive. I can't wait til those migrate into other systems. My goal is the 8" tablet. Thin isn't something I particularly need, what I need is small enough to fit in a hip bag, etc, so I can work from anywhere in a pinch.