I would second Aptana 3 as a replacement. Once I moved off of Quanta, I started using a ton of different editors. I mainly do front-end work, so I was mainly working with PHP, HTML, CSS and JS.
Here's a short list of editors I've used:
Eclipse w/webtools - Loved it when I was working on the SFDC platform. Everything you need and more.
Aptana 3 - gets a little slow when I'm running the Git plugin for it, and the auto-complete seemed slow as well, but liked how easy to was it integrate with SVN and set up virtually any environment for it. Lots of good plugins for it since its basically an Eclipse clone.
Komodo Edit - love it. fast, tons of plugins, great code hints and syntax highlighting.
Dreamweaver - ok, but missing a lot of the features I loved in Quanta and other IDE's.
Visual Studio - never was a PC guy, but had to use it in my last gig since the company was a big MS client. Was impressed with the features and functionality. If you're doing any
ASP.NET work, it's a no-brainer. I heard there's a similiar Linux editor called MonoDevelop which is available if you're a die hard Linux person.
Brackets - newer IDE from Adobe. Still in Beta release, but I like what I see so far. Already lots of plugins, some of the basic features are still missing like syntax highlighting (there's a plugin for css, but not for HTML and other languages) and integration with GIT.