Aptana could be an alternative, too. But I read a lot of really bad comments about it (slow, buggy)...
Regarding Visual Studio: PHP only via e.g. VS.PHP and for plugins in general (e.g. github) you can't use the express version so that will be quite expensive.
Btw. does anyone really use MS Visual Studio (Pro / Ultimate) with VS.PHP and can share his opinion if it's worth?