I've got to tell you I've been using Macs since the 512, and Apple II's before that... and OS X, (unix) is the best thing that has ever happened to Apple.
I do web and database design, as well as some digital video work, and OS X cannot be beat.
I run database servers on OS 9, Win2000 and OS X (10.1.5) and the one thing I NEVER have to worry about is the OS X machine crashing... OS 9 will drop on occaision, and Win2000... well 1 month of uptime is amazing if/when it happens.
I was running OS X Server v1.2 several years ago as a web server, and (although I LOVED the stability - hundred's of days of uptime without a glitch) I can see where complaints could be made about the GUI on that system, but OS X 10.1.5... the only real, valid complaint I can see is that it is a tad slower on older machines (I happily use it on my 266 wallstreet), but I think the trade offs (and time not spent recovering files) is well worth it!! I've got 4 Macs running one version of OS X or another, and only one running 9, and as soon as I get the cash for the OS X apps I need for that one I'll switch it over.
As for Tim's comment about Quark being the hold up for a majority of the mac community, what I can say is this;
Quark has been a headache for Mac users for years, and there "new" releases always seem to be 12-18 months behind what the should be doing. InDesign is here for OS X now. I don't use it a lot, but for what I do use it I dumped Quark 4 for InDesign 2... I for one was GLAD to finally be able to work without Quark.
Yes it took some time to learn the tricks of the new app, but the headache's of Quark are behind me now...
OS X is the future... OS X is the best OS out there... A few years I wouldn't have been able to say that, I would probably have talked about NeXTSTEP, a future version of BeOS or linux... But OS X has topped them all...