It’s always been said to new writers to not try to do series but to stick to single novels. While that is true for getting started (doesn’t mean you can’t leave the first novel open ended or have character’s that have enough back story that you can write more books) it doesn’t mean you can’t do it either. In fact, Goodreads. com listing of top Science Fiction of 2012-13 is nothing but series after series.
Kind of makes you wonder doesn’t it?
http://www.goodreads.com/list/show/20917.Can_t_Wait_Sci_Fi_Fantasy_of_2013