vxacid

A lot of people recommend PHP Storm, but I've never used it. I prefer text editors over IDEs. Check out Sublime Text 2 or 3. Sublime is extremely customizable, easy to use, and has an amazing library of plugins. There's also Coda which is similar, but you have to pay for it and it's an OS X exclusive.

OS X developer here! I own a windows desktop for occasional gaming, but I do most of my development on my Mac; I find my workflow to be infinitely better. The things that make it for me are the trackpad, the amazing battery life, and the awesome selection of apps. If you have the money, then definitely invest in a MacBook Air or a 13" Retina Macbook Pro!

If you have the money and the time, get a dedicated server. You won't get as much power for the price, but you'll have full control over your server! I got one from RamNode and I learned a lot about server administration and Linux in general. If you don't want to deal with that, however, then use DreamHost or Hostgator. Stay away from GoDaddy, they're pretty scummy people and their CEO has questionable morals.