I'm new and interested in getting a few postcounts...
My recommendation for a .rar extractor is actually 7-Zip, as in my experience it is MUCH faster than WinRAR (unless you pay up to remove the nag screens from WinRAR). It is probably the best truly free (no nag screens, even the source is open) .rar extractor out there (although it can only encode to ZIP and it's own 7Zip format).
My postcount is currently too low for posting links, just google "7zip" or "7-zip" and it will pop right up.