What is the best way to estimate how fast your site will load and find the fastest host, before signing up for a hosting company?

Some options I see are:

1. pinging the site from several locations (Note that most of my viewers will be in Western US)
2. checking server load
3. checking specs of machine that it will be hosted on
4. checking speed of similar sites

Which factors usually have the greatest influence on the speed a site loads? For a static page? For a dynamic page? If you have a high-quality server that is not overloaded?