What I use (and possibly, why?)

Computer

At home, it's a Macbook. The base model, it's been upgraded to have
4gb of RAM. I'd wanted one for a while, so when I moved to the UK, and
needed a small, easy to transport machine it was the obvious solution.
Especially as it had everything I needed already installed, and I
wasn't planning on playing any high-end games. It helped that I was
forced into using a Mac Mini at work, so I'd already been immersed in
the Mac way of doing things.

At work, it's a Mac Mini and a Dell Vostro. Neither of them is my
choice, but after trying to run a virtual machine on a Mac Mini with
1gb of RAM, I had to get a windows machine. And, sadly, it may
actually be more powerful then my Mac Mini. Still not as good as the
Macbook Pro that I'd like to use!

Browser of Choice

I flick between 3. Safari for general everyday things. It also has a
decent set of developer tools. Not as good as Firefox, which is great
because of Firebug. Last, there is Chrome. Used on the Windows
machine, it's fantastically fast.

So basically, FF is for work purposes. Firebug is unbeatable as a
development tool, and the way it reloads Javascript inside iFrames
(unlike other browsers) means that it does everything needed. Safari,
as mentioned earlier, has some useful development tools built in. Not
as much as Firefox, and it doesn't have the ability of Firebug to
change CSS or HTML on the fly. However, the speed of it ensures that
it sees almost constant use googling things, or just inserting
content.

But. Chrome is brilliant. Even more streamlined then Safari, it
also runs faster. The ability to go to a URL or do a search from the
address bar is great and makes things so much quicker. The only reason
it isn't number 1 is because it doesn't run on a Mac. Odd choice by
Google that.

Developing

Eclipse. The colouring of code makes spotting problems and reading
what things are doing much easier then the bad old days of notepad.
Plus it synchronises with SVN repositories. The only downside is the
problem it has with each project, whereby it can't figure out which
variable to use and stops working for about 20 seconds. Annoying, but
I put up with it because of the other advantages.

Along with WAMP or MAMP, there really isn't anything more you need
then Google :)