NetBeans. It's a very heavy IDE made in Java but I really like it for Java, C, C++, PHP and HTML5, it's a big plus to me I can use one IDE for all of these and I think it handles them all very well - coloring, project management, completion, documentation, ect. I mostly use it for C and C++ (which I know a lot better than the rest of the languages it supports) but whenever I needed PHP, Java or HTML5 it was perfect for me as a newbie.

In general, there is no universal best software for doing X. Different people find different things more important, so everybody has a different solution for "best".
This is in particular true in open source, where there exist 5+ pieces of software for every job you can imagine.
This also means there is only one person that can decide "best" for you, namely yourself.

I have started using the following strategy to find such software:

1. Find a random piece of software that claims to do the job.
2. Read about, try it, use it briefly to check it does what you want. If not, go back 1.
3. While happy, continue using it. It doesn't hurt to keep your ears and eyes open for other software, there is also not much need to switch.
4. You have an improved idea of what is important in "does the job". Go back to 1

You can also consider using hybrid forms. I use Eclipse for code that uses an API I am not familiar with, the auto-complete is very useful then.
On the other hand, for lots of small changes in large amounts of code, I use gvim.

I'm a big fan of WebStorm for JavaScript. It's more expensive than some other options, but it's a really great product, and there's a free trial available to see if you like it.

Seconded. I've tried a lot of Javascript IDEs but WebStorm stands out above all the others.

If you want free then its probably a toss up between Aptana or Netbeans.

I'm a big fan of WebStorm for JavaScript. It's more expensive than some other options, but it's a really great product, and there's a free trial available to see if you like it.

Seconded. I've tried a lot of Javascript IDEs but WebStorm stands out above all the others.

If you want free then its probably a toss up between Aptana or Netbeans.

Thirded. I found WebStorm to be super awesome when working on a MEANjs powered game. The code lived on linux, but I worked on my Windows machine and connected to it seamlessly with WebStorm.