What are the best free software products that improve productivity? [closed]

Solution 1:

One of the best compilation of productivity tools for developers -- at least for Windows -- is

Scott Hanselman's Ultimate Developer and Power Users Tool List for Windows

Many, but not all of them, are free.

Solution 2:

Google Reader.

No, really.

I use it to read the blogs of tons of great programmers, which is a great learning tool in and of itself.

But, then, when I find a particularly interesting tidbit, I'll tag it and save it for later.

I have different tags for different areas of development, so when I need help or advice in a particular area I go to that tag and I have a treasure trove of applicable advice and code-samples waiting for me.