Thanks again for the help. Looks like MBA can run WoW for sure.
I'm on the fence still to switch, though this answers a key question for me. At this point I've decided I definitely want to go MBA, it's a question of when (between now and 3 years).
I have a single computer: a 5 month old 15" MBP 2.4Ghz. At home, I have it hooked to a 20" widescreen Dell about half the time too. I play WoW, have Logic Studio installed though haven't had time to use it in a while (I might downgrade back to Garageband, which works well enough for my purposes though it isn't nearly as powerful). I have some programming stuff installed (MySQL database, requires about 5GB), and Parallels with XP which I use maybe twice a week just for a few minutes to test things in IE for my job.
By far the most frequent applications I use on a day to day basis are: Safari, Mail, iChat, iCal, Address Book, Terminal for programming/MySQL, iTunes, and NeoOffice (word processor/spreadsheet). Offhand I don't think I use anything else for work besides Parallels occasionally. I play WoW on some weekends but am not a power gamer. I haven't had time for music composition in about a year (got so much other stuff going on and this is unlikely to change the next few years).
The reason I'm thinking of "downgrading" from 15" MBP to MPA is I telecommute, and work out of coffee shops almost every day. Also, I travel to meet team members or clients for most of the week once every 3 weeks. Even at home when I'm working, I work off my couch with the laptop on my lap half the time. The weight and size savings are a huge, huge plus to me, certainly enough to justify getting worse performance in WoW. Much as I love WoW, for every hour I play WoW, I spend 10-20 hours on the plane or on applications for work/personal stuff that doesn't require a powerful CPU/graphics card (certainly when I had a Mac Mini it worked fine for these purposes). I even work at restaurants/bars sometimes, and the benefits of getting the full-sized keyboard, a still nice 13" display, and all my applications (besides Logic Studio which I haven't used anyways) in a notebook that is easier to carry would be awesome.
I think if the MBA had EVDO Rev A (broadband wireless 3rd Generation-- I use this through a Sprint USB device), and WiMax or another 4th Generation broadband wireless, and an extra 40GB of disk space, there would be no question even if it was $2300 instead of $1800.
At this point, I think the only thing holding me back is the hard disk space. Already for my MBP, I don't have any songs or movies on my local hard disk -- they are on my wireless network and my iPhone. I'm using about 133GB.. I'm hoping a lot of that is Logic Studio.. I seem to remember installing a lot but can't remember if I installed all 4 or 5 DVDs worth of data. There is another thread I saw that explains how to save some disk space by deleting unused printer drives and languages.. that will really come in handy as this might come down to the wire a bit. Anyhow I'm going to have to go through all my files with a fine tooth comb to weed down and see what I really need.
Btw I went to an Apple Store a couple of days ago and the Apple employee went on a 5-minute tirade about how I would be really a fool if I downgraded my MBP to MBA. It was kind of interesting, he really had a strong opinion that I would be making a colossal mistake. But looking at which applications I use, how much CPU/GPU power they take, etc (and that 90% of them run fine even when I had a Mac Mini), I think I would take only a very minimal hit there, and come out ahead hugely in terms of weight/convenience switching to MBA as my sole computer.
Probably I will switch to MBA pretty soon, just thinking it over for a few more days (and of course I need to go through my disk space usage extremely carefully to be sure this will work..)
Still weighing the pros and cons on this decision.. thanks again for the valuable feedback.