@Grant, et al.
Actually, Photoshop for Windows runs fine on my Linux box through wine, with no noticeable performance impact.
But I want to throw in my tuppence here.
Unlike most other really big software vendors, Adobe has to my knowledge always maintained a relatively user-friendly and open-minded attitude -- as opposed to the likes of Mi¢ro$o£t, Macromedia or Quark (or SAP for that matter). I am one of those who still fondly remember using Photoshop 4.0 for Solaris and being awed by its performance (thanks for the SPARC III, Sun!).
Adobe is the only major software house out there that seems to have hung on to the vision of its founders: to produce superior software for the customer (and, of course, make a lot of money with it. But that's everybody's vision, innit?). They have been rather reluctant during the last decade to develop for anything but Windows (used to be that their Mac releases were the development leaders; by the late 90s the Mac versions of their apps would lag up to half a year behind the Windows releases. By now, they release both simultaneously).
But after a long delay in getting the next Adobe Reader out for Linux (they left out a few major releases), they seem to have realized that there _are_ Linux customers -- and maybe enough to make it worthwhile to actually develop more software for Linux.
Don't hold your breath for a version of Photoshop that runs natively. Those who are willing to _pay_ for Photoshop and want to run it on Gnu/Linux are few and far between; my guess is that about 70 % of all installations of Photoshop currently in use are pirated. (Don't look at me; I'm fully registered.)
Of course, Adobe is only going to consider developing anything commercial for paying customers. For many Linux users, the GIMP is good enough and then some; frankly, in a few places it outdoes Photoshop. For the other Adobe products, the situation is similar; Inkscape is a quite capable vector drawing application that in some places rivals Illustrator, for viewing PDF files I'd use anything _but_ Adobe Reader, web development solutions abound (and the more visual tools tend to write cleaner code than Dreamweaver or GoLive; most serious web developers use non-WYSYWIG editors anyway), and so on. I'd say only InDesign has no direct OpenSource rival, since Scribus is still somewhere in between PageMaker 5 and XPress 3.3.
So, everything considered, I'd say I am looking forward to more software offers from Adobe for OpenSource OSs -- how about porting some of the Mac versions to BSD? Granted, the GUI bits would need some doing, but the actual back-end should be easy enough to port. And once they've gone that far, hey, POSIX, Linux would not be all that hard to do either.
Just don't hold your breath, is all. If they're going to do it, it won't be this year or the next. My estimation is that they're doing AIR for Linux because lots of software developers use Linux, so it's a logical thing for Adobe to do at this time.
Still, coming back to how Adobe is different from the other big ones: they actually do this thing. Don't expect anything like this to come from the company that dropped Minix in the mid-90s, or any of the other semi-monopolists.
Disclaimer: I am not, have never been, and most likely never will be employed at or otherwise associated with Adobe Systems apart from participating in a few beta test programs in the 1990s.