On Windows, I use a text editor called Programmer's Notepad. It is the best light-weight text editor for programming in Windows from my experience.
Apart from the standard text editor features of syntax hi-lighting, highlighting matching braces etc., PN has a nifty feature of highlighting similar text; very useful following a variable or an object through the source code.
Aptana Studio is my choice of IDE for all serious projects. Aptana doesn't seem to have the aforementioned feature. Actually it does, only it comes disabled by default.
To enable similar text highlight feature in Aptana: find the marker icon on the toolbar (Mark Occurences) and click on it.
Looks like this feature is disabled in Aptana by default temporarily due to performance issues.