Great list by @Doom One other web site that I use, Alliant.Just my two cents. This is my experience.
Picking one of the major bullet manufacturer's books is a great source of information, not just load data. With the rapid evolution of powder almost all if not all of the manufacturers put their load data on the net.
Personally, I don't like Hornady's load data but the rest of the information is great. I find their data too conservative.
Sierra and Nosler have their load data on the website or a free app. If you plan on shooting Berger bullets then I would recommend their manual for it's load data. Personally I shoot predominantly Sierra and Berger bullets with a little Nosler and Hornady thrown in from time to time.
So what do I have and use?
Nosler 6th Edition & Website
Hornady 8th Edition
Lyman 49th Edition
Sierra App
Hodgdon magazine & websIte (I use VV and IMR powders for the most part)
VihtaVuori website
I need to purchase the Berger manual.