Scifi isn't something I have read a lot of (I usually go for fantasy, historical adventure, and spy/hard/polit-thrillers), but I just swept through Jack Campbell's Lost Fleet, Beyond the Frontier, and Lost Planet series, and I really like the books.
I'm looking for something that is similar, though wouldn't mind a stronger focus on exploration (new species, etc.). Hmm, maybe something between his books and the Stargate:SG1 TV series?