I'm like Mr. Sith only worse. :) I plan to make 16 characters right off the bat, 8 republic on one server, 8 empire on another. Each AC on each faction, and I've already divided them up so I don't play the same spec on mirror'ed classes.
I won't play ALL of them at the same time. In fact, I refuse to have a "policy" on that. I play what I feel like playing at any time, it helps keep it all fresh and interesting. Sometimes I focus on a character for a few weeks, sometimes a few days. Some of them get ignored for a long time, and then I get excited about them and play them for a while.
I'll probably try to get many of them up to 10 to get their AC and crew skills. Beyond that, well, I find the stories pretty captivating, so I may focus on a single character for longer periods than I have in other games, because I don't want to put away the story line. That remains to be seen.
It is tempting to push a particular character to the end of chapter 1 to get the legacy system rolling, but I generally have trouble playing one character that long. And I do like always playing rested, it helps compensate for my alt addiction if I'm always getting bonus XP.