Yes, Mark Pellegrino! One of my favourite actors, he's just so cool. He once sang Sweet Transvestite on some Con and since I saw the video of that, I just can't help but giggle and fangirl whenever somebody mentions him.
And yeah, War's there too! \(^_^)/ *fangirling*
I googled around a bit, and I think you might mean Mark Sheppard. I've never watched Battlestar Galactica, but according to IMDb, Mark Sheppard played a dude called Romo Lampkin in it. But yeah, Sheppard is actually in Supernatural too. And not just as some punk-ass crossroads demon. In fact, he's the damn king of hell, Crowley! :D
And yeah, War's there too! \(^_^)/ *fangirling*
http://www.imdb.com/name/nm0719678/?ref_=ttfc_fc_cl_i23
I'm always mixing him up with Leoben in BSG.
Edit: He was also in Supernatural as Wendigo, apparently.