Yet another "Which iMac should I buy?" thread (for Aperture/Logic)

I started as one of those people complaining about the new iMac's lack of user upgradability, lack of optical drive, and thinness for the sake of thinness, but after researching every Mac that Apple makes, I'm coming to the conclusion that a 27" iMac might be the best computer for my needs. I'll be upgrading from an early 2008 MBP connected to a 21" Samsung LCD monitor from 2001 (which still works great), so I expect that any recent Mac would be a huge improvement. For email, web browsing, e-books, and portability, I primarily use my iPad 4. The Mac is for serious amateur photography and music. I use Aperture 3 (about 6,000 photos in my library), Adobe Photoshop Elements, and Logic 9. I tend to keep my computers until they become unusably slow. During the lifetime of my next computer, there's a good chance I'll also use it for video and other digital art, such as Corel Painter. I don't play games – which is where my needs differ from most of the other similar questions on this forum. Most of the "Which iMac should I buy?" threads contain the advice, "Well, since you're a gamer, you'll want to consider such-and-such..."

I'm thinking that the base-model 27" iMac, upgraded with a 1 TB Fusion drive, is a good choice. I want 27" for the real estate. After getting used to a work computer with an SSD, I can't imagine buying a new Mac with a conventional HDD. The 768 GB SSD is out of the question price-wise, so the Fusion drive seems like a good alternative. I'll start with 8 GB of RAM and upgrade later with third-party RAM if I need it. This combination is $2,049. Given that I do keep my computers for a long time, though, I'm willing to spend more for an i7 processor and/or a better graphics card, if they'd provide noticeable benefit for my needs.

I'm also considering a MacBook Air, but I'd wait for Haswell because of the better integrated graphics. The advantages would be portability (which would be a "nice to have" feature, atlhough, as I said, my iPad 4 is good for portability, except when I do heavy typing) and lower initial cost. I'd continue using my Samsung monitor until the next Thunderbolt display (with USB 3.0) comes out. I know that the iMac has a faster processor and graphics, but the question is, would an iMac be signifianctly faster for what I do, or only slightly faster?

Thanks, Zwhaler and tuccillo. For a computer that I hope to keep for several years, both the i7 and the 675M graphics-adapter upgrades are reasonably priced. That would only be a total of $400 above the base price of $2,049 I was looking at – which, spread over four or five years, isn't bad. And if I'm going to do that, maybe I should spend an extra $150 for the 680M.