I got my first mac(book) recently. I gave Safari a short go, but I wasn't really interested in configuring it the way I want to browse (finding out how to get tabs and so on), because I think there are two good reasons not to use it no matter how good it is relative to the others.
What I'm saying is, you shouldn't even give it a fair chance.
1. In usage polls, Safari is almost as common on OS X as Explorer is on Windows.
If someone wants to insert malicious code on web sites that targets Mac users, they'll be expecting Safari. Everybody has it installed and more people are using it than the other browsers combined. (I don't remember where I saw the statistics, sorry.) While there aren't any serious viruses for OS X that I know of, exploits are discovered regularly just like for every other OS and browser. Lately, it seems all the exploits I've heard about have been for rendering objects like image files with Apple's Web Kit, which Safari uses. One set of exploits allowed to run any code on your computer by embedding it in a JPEG. Avoiding Web Kit also means not using the other browsers based on it, Shiira and the rest.
2. You've got Safari only when using a Mac.
I don't know about the majority of Mac users, but I'd bet that a lot of you also have PC(s) or use them at work. Whether Windows, Linux or some other OS, you won't have Safari available. So getting too used to it might not be a good idea. Exporting your settings won't be too easy and you might have no idea how to accomplish something you're used to doing. I even use mostly web mail instead of mail clients because I don't want to depend on any specific computer, so your habits may vary.
So, what should you use then? My Firefox experience has been quite free of troubles, so I can recommend that. The extension paradigm means that a new install takes a little more time to get going than something like Opera, and using Firefox on a friend's computer might simply mean you can't do things the way you like to because of a different set of extensions. I was using Opera before Firefox and I'll be trying it again once Opera 9 comes out.
Firefox has been good for me, but I'm going to check Opera out because of mouse gestures (must have extension for Firefox, for me) being better integrated into the browser there. If I recall correctly. In Firefox, the browser can be unresponsive to my gestures when the tab I'm on hasn't loaded yet, and some similar situations. Opera also has a smaller memory footprint, it's consistently fast across different platforms (I've read that Firefox is slow on OS X compared to other systems, although I haven't really noticed much.) and a default installation of Opera has almost everything I want. (The rest doesn't count as bloat to me when the whole browser is still so small and fast.

) Things to make me want to stick with Firefox are all the existing gazillion extensions (I can find some really obscure stuff that only a small minority that I belong to would find useful.) and better (known) market share: you'll find more web designers remembering to check their site with Firefox than with Opera.
Oops, kinda long post again... Oh well, I hope you make up your mind and try stuff out, and hopefully even end up with a non-Safari browser!
