I'm using Jamil's calculator, sort of. His calculator uses the 1 million cells x 1 ml wort x 1 degree plato and factors that down by some amount, looks like to about 80% of the value you get from that equation for ales. For a 1.095 ale he comes up with 305B cells. I had factored that down a bit more but after looking at it again agree that it should be higher. Probably up to the full amount called for by the equation.
After I figure out the number of cells I'm shooting for I'm using the table on page 68 of How to Brew to decide on the starter size.