Ensure Ease of Recovery with Asigra’s Agentless Software
Onwards and upwards... mostly
And the new OS was also retrograde step in some ways. The Classic Mac OS' Finder, for example, had always established a direct link between how files and folders are viewed and their state. The Mac OS X Finder was, and largely is, merely a file browser - a presentation of files and folders somehow separate from the entities themselves.

Tweak your window toolbars
A subtle distinction, true, but one that cut to the heart of the 'what you see is what you get' (WYSIWYG) philosophy that set the original Mac OS apart from others.
Die-hard users may have grumbled - they sure did - but plenty of folk got on with it, got used to Cheetah's inconsistencies, some of which were dealt with in the 56-odd OS X releases that followed OS X 10.0's 24 March 2001 arrival culminating - so far - in Mac OS X 10.6.7, which was released just a few days ago.
Little things aside, OS X brought Mac users memory protection - so a crashing app wouldn't kill the whole system, a not uncommon event even in the Mac OS 9 era. We got out-of-the-box support for multiple CPUs and eventually multi-core processors. We got built-in internet support. Geeks got a command line. We got a great-looking UI.

Modal dialogue boxes out, sheets in
OS X has changed over the years, but in no way so much as its price. Snow Leopard - aka 10.6 - costs $29 / £26. Apple wanted $129 for Cheetah. Thanks to inflation, OS X ought to cost $161 (£98) now. ®
Requirements Checklist for Choosing a Cloud Backup and Recovery Service Provider
COMMENTS
Happy Birthday Indeed
*THIS*
This is exactly why it's so stupid for the fanboys on both sides (sorry - all sides) to quit their moaning.
Whether your favourite is OS X, iOS, Windows, Android, Linux, whatever. They all impact on each other, and overall we all benefit.
Well - if companies would stop sueing each other every ten minutes for copying each others ideas.
@Jake
You bang on all the time about how great FOSS is and yet you complain when it's used by companies of whom you don't approve? You seem to miss the point that FOSS is given away by developers who want others to use their code. If the developers didn't want any commercial use of the code, they'd use an appropriate licence.
What next, maybe we shouldn't be allowed to run COTS on linux because we're paytards?
Hmm...
I always wondered why Apple used the cat naming convention, considering that the MacIntosh family motto is: "Touch not the cat, but a glove"
Roughly translated as "Don't stroke a wild cat without a chain mail glove on, becuase it'll have your face off"
Do they know about the MacIntosh/cat links, or is this just a coinsidence?

IT infrastructure monitoring strategies
Requirements Checklist for Choosing a Cloud Backup and Recovery Service Provider
Data control in the cloud
Cloud based data management
Enabling efficient data center monitoring