I had a tough time choosing, but i voted battlestar over alias. i love JJ abrams (writer/creator/director/producer: alias, felicity, lost) and alias is a top notch spy show, best i've ever seen anyway, in season one and two. the chracters are what get me in all JJ's shows. they are all very interesting and deep, and he makes you care about villains (see: sloan, ben, zack(i think?-pseudo-rapist on felicity). are they really evil? anyways, sorry for ranting. battlestar is hands down the best work of sci fi i've ever seen. it's a great plot that stands it's own for two seasons. Watch both, but battlestar first.