Try the Drake equation. Estimates of the number of intelligent and communicating civilisations in the milkway galaxy range from 1 to numbers in the millions. Personally I think it's something like 10,000.
http://www.activemin...e_equation.html
Some people even believe that Pulsars are the galactic equivalent of the communication satellite because their pulse rate is so constant. This is commonly doubted, however.
How many advanced species could have developed faster than light travel? That is the real question.
Ah, good question. The Drake Equation is something we'll have more hard data on within a few decades, as jovian moons get explored, and Mars is more extensively explored to determine if it ever held life. If we are optimistic, and assume that Mars once held life that was killed off, and two moons of jupiter and one of Saturn hold benthic life forms under the ice, then we can come up with a rough guestimate that stars with planets in near circular orbits bear life 40% of the time on the planets or their moons. 4/5 of lifebearing ecologies survive climatic changes, and 1/5 of life bearing planets develop intelligent life.
I'm also going to go out on a limb and declare that if you are smart enough to figure out how to build nuclear weapons, or engineer pandemic diseases, you are smart enough to figure out what a dumb idea it is to exterminate your species with them, at least 50% of the time. However, I'll also say that, unlike nuclear holocaust, a natural instinct against mutation or malformation, survival xenophobia/luddism, will be a huge force against acheiving uploading.
I'm going to be practical and assume that FTL does not exist for macro-sized beings like us. Its too damn expensive to move meat from star to star. I will also say that meat people don't interest data people except as research subjects, or perhaps pets, but never explain to them the data persons true nature, so we'll never interact toe to toe with alien species until after uploading. If your species remains luddite, you never meet the aliens.