Can I have pages, iPhoto, Safari, iTunes (under five) open at once on a MBA Rev A? Will it go crazy and slow? I'd imagine 2 gigs of RAM would be able to handle a couple apps.
The short answer to your question is the MBA 1.6/80 will run everything you list at once and much much more without any issues whatsoever. The longer answer follows...
The MBA is one if the most controversial Macs to come out in many years. It seems to polarize people and there are a lot of MBA haters out there - even Mac fans. Specs are not everything and like most Mac's the MBA is much more than the sum of its parts. Like any product, its not perfect, and there are some number of defective units as well. Given its price point issues were magnified and while I don't discount the fact that some people had some issues with some machines, I know a lot of MBA owners that are very happy (including myself).
When I first got the MBA I was worried about its limitations and invested in software like Appdelete, iFreemem, iDefrag, Bokeh, SmartSleep, and Xslimmer. While All of these are fine programs, I really did not need any of them but they all do provide some benefits. In order of most to least:
a) Xslimmer saved several GB of space and most apps start up noticeably faster.
b) SmartSleep saved a couple of gigs of disk space and allows faster slwwp/wake cycles
c) iDefrag is not something you have to do often unless you are running your disk > 80% full but it improved boot times by about 20% and some programs and operations are a bit faster.
d) AppDelete saved me several GB of disk space but you could get the same benifit by loading OS X from scratch and choosing options not to install any apps, drivers, etc that you don't need.
e) iFreemem makes you feel better by seeing more free RAM but I'm not sure it actually improves performance over OS X's memory managment other than preplanning garbage collection before starting something big.
f) Bokeh - allows you to dedicate all your CPU to a single app and/or freeze indivisual apps. I never really needed it for the reason I bought it but it has come in handy a couple of times when an app goes wiled and consumes a cpu until you figure out whats going on and stop it.
I routinely run about a dozen OS X apps, plus a Parallels Windows XP VM plus a few Windows apps all at once with great performance. Video causes the fan to max out and temps to rise but not excessively on my unit (and no core shutdowns). The only thing that I've found that renders performance unacceptable is doing large file transfers (like an image backup) while trying to do other things. I imagine trying anything disk AND cpu intensive (like ripping a DVD) would also adversly impact other apps.
But I'm extremely happy with my MBA. I use it 10-12 hours a day for work and think its great.
Good luck with your choices.