Wow, one of my favorite computer subjects and I've missed most of the discussion!
There really is way too much for me to reply to here, but I have a few random (really, truly, random) thoughts:
In response to someone earlier in the thread: graphics apps are actually seldom made on or for Mac anymore. There are far, far, FAR more graphics apps of all kinds available either Windows-exclusive, or cross-platform (e.g. Irfanview, XnView, Paint.net, Faststone, etc, etc.). The only apps really made for Macs now are Adobe and Apple's own, of course. Apple has purchased a few major developers (e.g. Finalcut devs) to make them platform-exclusive, but before that they were cross-platform.
I don't think the "Photoshop is made for and works better on Mac" argument holds up anymore, not for several versions at least. If I recall 64 bit CS4 was massively delayed on Mac this generation, a big signal right there. Apple does a lot of things wrong behind the scenes in the coder's world. If you've ever talked to someone coding for the Mac platform and just trying to get things done, you'd hear all about it. I know because I work for a company that makes a cross-platform graphics app, and some of Apple's decisions really defy belief.
In regards to businesses converting just because a generation of people become Mac users (which they aren't - Macs still have very much a minority of even consumer-level systems), that won't happen because - with the exception of small or niche businesses (e.g. graphics shops) - what businesses use isn't largely dictated by what their employees know and like, it's dictated by an IT department who will always be savvy with Windows or whatever platform best enables them to do their job, and it's also dictated by business software availability and support, which is still largely MS or at least Windows focused. Apple seems to ignore this market fairly consciously, too. They probably aren't all that interested in the low margin business market, and who can really blame them. People always talk about Apple reaching these new markets with apparently the mistaken assumption that all markets are necessarily worth owning, but Apple proves that being a minority player can still be extremely profitable. Apple puts in probably about 10% of the effort that MS does, and reaps 90% of the reward that MS does with a far larger market share.
As for why Apple keeps marketing the way they do, well of course the answer is *because it works*. What other reason is there to use marketing of any kind? If truthful marketing campaigns that showed actual users would garner more users, naturally that's what they'd use. But I think that in itself shows you that OS X *can't* be that much better, otherwise they would use those tactics. Even WWDC and other Apple events, where they *do* show stuff in action, are actually paid attention to by a relative minority of Mac users (let alone computer users overall), and they're not a primary marketing piece. If those demos were so good at selling Mac's features and stability, they'd be the ads, but they aren't. Instead we have smarmy Justin Long basically just standing by letting the PC screw everything up, and then casually, almost even reluctantly pointing out that Mac is the obvious, superior option.
Here's what's interesting about all this, and it's been at least touched on, if not fully discussed already: the only reason any of this works, the only reason the Mac platform has any kind of edge (and that edge certainly isn't in market share - 10% overall), is precisely *because* of its "underdog" status and the relatively small size of its market. Give it a 90% market share and
A: more users, more problems
B: to get there they'd have to lower prices and lower margins, which means less budget to do great design, possibly the need to shop out system construction to 3rd parties again and thus broadening hardware support requirements and lowering the reliability of the OS
C: bigger target for viruses and other malware
D: (and this is the one few consider) given what happened to Microsoft re: antitrust, and looking at how Apple is doing *way* worse things in this regard (forget just bundling a browser or media player, they bundle everything, plus *force* installation of apps you don't even want on your system, even if it's *not* a Mac), it would be shocking if Apple wouldn't be subject to the same kind of sanctions
What you have to ask yourself when considering Macs and where they will go is, has BMW become the most owned car in America? Will it ever? No and probably not. The only way that would ever happen is if BMW weren't a luxury manufacturer. They are defined by their market. Change the market, and you change the product, change the company, change everything. The same is true of Apple.
So do I see Apple running away with the business market or becoming a huge success in the true mainstream? Nope. Would I consider it as a platform for my own computing needs? Sure, as soon as they let me customize the UI more. That's my biggest complaint with the OS, honestly. Not even general customizability as that's actually fairly good if you're willing to dig into the commandline. There's a whole community of OS X hackers just like there are Windows hackers, people like us here who like tweaking and tuning to get the most out of the OS. You don't hear as much about them because OS X as a platform is supposed to "just work", but there are plenty of people who aren't satisfied with how it "just works" out of the box and work to make it "just work" in a different way.
The UI though is somewhat more rigid as I understand it, and that's a big part of what keeps me away. That and the lack of more system-level utils like better file managers, which someone else mentioned. But I still keep an eye on what they're doing and I hope that one day they do decide to offer a more "serious", "geek" line of systems and OS products, sort of an unlocked version of the Mac experience. But I doubt it - it'd be a big threat to their cash cow, and what sensible business would want to do that just to satisfy a minority of potential customers?