Cristian,

I installed ZSE (which includes PDT) and Aptana as plugins to Eclipse, which btw is a PITA as ZSE has some dependencies which can be tricky to track down its much easier to install Aptana into the standalone ZSE distribution.

The nice thing about eclipse is you can switch perspectives at any time. phtml files I usually start in Aptana perspective then will switch to php perspective when I start adding more logic. Of course I attempt to keep any php in my phtml files to a minimum.