I understand the concern, but honestly computing power in these machines is just phenomenal for what they are. I myself am still using an Oct 2007 2.4Ghz Santa Rosa Macbook Pro (maxed with ram, and "high" end GPU 8600m GT 256MB!), which really is almost for all intents and purposes, now less powerful than the i5 MBA. GFX performance is slightly better, but not by much honestly. I use it for IT administration, some iMovie work, and a little gaming, and its just dandy even today.
It's just the screen resolution and size that have kept me in the 15" market rather than jumping on an Air, even though the Air would just about suit all my needs/ performance. I know geekbench is not all too useful, but my 2007 machine scores about 2000 less than the 11" i5 air (3300 running off an Expresscard SSD) vs the i5 Air at about 5000. Now if only there was a Thunderbolt dock similar to what the new Sony Vaio Z has...
I do go through a battery every 10 months though...457 cycles so far since the last one....and I need a new one again...