You have a pretty good setup already, which is very close to my own.
XAMPP/WAMP: You're not going to get around this one. You will want to enable Xdebug, though, so you'll be able to step through your PHP code the way you're doing with your Javascript now.
Eclipse: The main selling point for me here is Mylyn, which lets you switch between contexts with literally one mouse click. This is invaluable if you're working on several projects simultaneously (or have to go back to older projects every now and then to make a change), and although Eclipse sometimes drives me mad, no other IDE provides this kind of functionality.
Chrome/etc.: You will need debugging tools for all your browsers, so you can track down browser specific bugs, but luckily all modern browsers come with their own tools anyway. Using Chrome for main development purposes is a good choice.
I'm also running a SASS compiler in a Ruby process during development, which is very handy if you're sick of writing redundant CSS. Have a look here:
http://sass-lang.com/