Posting in the Magento forums has been disabled pending the implementation of a new and improved forum solution which should better serve the community.
For new questions please post at magento.stackexchange.com, the community-run support site for the Magento community. We will be providing updates on the new forum solution soon. For questions or concerns please email email@example.com.
We use Aptana, and it works out great. One of the best things about it is that it will index the classes and functions in your project and give you code completion! You’ll only need to pay for the Professional version if you need SFTP and some other features like unit testing.