Definitely use Firefox. There are plenty of plugins that will help you with getting stuff you need (Media: Video DownloadHelper, Skipscreen, Greasemonkey), (SEO/Dev: Search Status, the Error Console, AutoProxy, Scrapbook, FireFTP, LiveHTTP Headers) and so on. I use everything I just mentioned, plus a few other things.
As for native apps, I would have to agree that there aren't very many "built for mac" bh tools, but Market Samurai is still excellent and you can get it for free on here. I use Parallels to run windows and/or linux apps. AppCleaner is a great app to get uninstall ANY app you don't want any more. It's just plain drag-and-drop.
I use Freemind for mindmapping my ideas and you can import mindjet files or anything with the .MMAP extension.
VLC is pretty awesome for opening up almost any type of media including FLV files you snag when using the Video DownloadHelper!
There's a program called iSquint that can take your FLV files and convert them to iPod format or TV with a simple drag-and-drop. Useful for quick conversion.
Of course if you want to set up your own server, you will definitely want to get MAMP because it's just plain awesome. Just make sure you get the VirtualHostX so that you can create virtual domains to test everything on.
Before I forget, make sure you have Stuffit Expander to open up any archived (zip, rar, etc) files. It just works.
Oh by the way, everything I mentioned should be FREE. I'm frugal.
Hope this helps.
Later.
