The Apple-vs-Adobe "war" has been going on ever since Final Cut first appeared. Adobe got all huffy that Apple was derailing their gravy train by selling a superior competitor to Adobe Premiere (at that time a rather lame product that Adobe had neglected.) Adobe's response was to start neglecting development of its other products for Apple, and to start recommending Windows and telling the authors who write guides to its products to start doing the same (the how-to books written by Adobe-captive authors of this era are full of introductions stating that Windows-whatever is "the ideal platform for running _____.")
The software-neglect side of the strategy petered out after a while, but Adobe is still huffy and I expect Aperture will make them even more huffy and vindictive.
Which is a shame, because it looks to me (a graphics-industry professional) as if Aperture isn't really going to take away anything from Adobe's product line. If anything, it enhances it.
It's obvious that Aperture is NOT intended as a competitor for Photoshop. It's an organizing tool. From the specs, it appears to include a good selection of rough-cut editing tools -- but if you need to do any serious retouching, compositing, etc., you'll still need to go into Photoshop (and Aperture includes features to make this easy.)
If Aperture competes with anything in Adobe's product line, it would be Bridge -- which only comes with Creative Suite applications and doesn't earn Adobe any money. I like Bridge a lot -- it's great to be able to see rendered previews of raw files and do non-destructive cropping and levels adjustments.
But Bridge still goes only partway: You can't do any other prep work on raw images without converting them to another format, and you can't save catalogs of images to store offline without using another application (I've been using iView MediaPro.) Even the cataloging applications that support raw image formats such as DNG don't really catalog the raw image itself -- you're looking at low-res JPEG previews, so you can't (for example) zoom in to check the sharpness of a detail without reloading the original media and launching an application such as Bridge.
A seamless, all-in-one solution that lets you prep and catalog original raw images will be a huge productivity booster for photographers who shoot a lot of raw files. For those people, it will pay back its $500 list price in a matter of days.
If Adobe had marketing sense, it would be cutting a deal with Apple right now to offer a "pro photographer bundle" of Aperture, Photoshop CS2, and Acrobat Professional. But as I said, I expect they'll stick with being huffy and defensive instead. Too bad.
PS -- The one unanswered question about Aperture that's relevant to this forum: Will it support Epson R-D 1 raw files? The R-D 1 isn't on the list of cameras with "optimized" raw-file support -- but I don't know whether this means there's no support, or just basic support.