Sure your hardware is pretty low, what is very important for a VM is also the hard drive speed, and the mac book air has a pretty lame one (except if you have the SSD option)… so sorry I can’t assure you that your experience will be as good as mine.
My advice would be to use the Parallels 5 trial version , setting it up is pretty straight forward and see if it works for you.
Having used Parallels 5 for a bit now, how would you describe its stability compared to VM-Ware? The consensus seems to be that with VMWare you trade speed for stability. Has that been your experience?
A related second question, how much do you think your positive experience with these two is based on the quality of your hardware? I’m running the latest Macbook Air, which tops out at 2GHZ duo and 2GB Ram. I don’t plan on doing any graphics work besides basic maps (GIS) and Microsoft Office. I’d do boot camp, but the clunky file-sharing options with that seem prohibitive.