True aptana has a lot of good features but it's big (over 150 megs compressed download - but that includes video tutorials) but I found it made a lot of things complicated that didn't need to be. Where in most editors you just 'create a new file' or 'create a new project' you couldn't just create a new file during the months that I was trying aptana. You had to create a stupid container for the file first before you could create a new file. The update features and plugins I tried never worked. That said it's been about a year since I last tried aptana so it might be worth another go. It is not for those who want something 'light' though
Quanta Plus is always a good fairly light weight editor.
Lately I've been using VIM more though. For small scripts and projects I find something nice and lightweight is always a great way to go.
I wish there were some good RAD tools for PHP for the bigger projects. I've tried code-igniter and it definitely wasn't for me and I'm not much of a framework fan.