I'm wondering why nobody has mentioned Zend Studio. It's been years last time I touched PHP code, but I used this IDE and it was almost like being in Visual Studio (minus the Visual part of course). I'm sure it has come a long way since then.
Looks quite expensive to me at $299 for a year (or $617 for 3 years) with updates and then the same again every year (or 3) if you want to keep updating as things change. OK there is a perpetual license to use the software but it would be nicer to have a reasonable purchase charge and then a smaller annual service charge.