For me, it's all about the jawline. Baltar has a strong, long, broader jawline. Clive's is weaker, more feminine, almost comes to a point. And Baltar's hand is larger, more masculine yet still has an elegance about it. His mouth also wider, bigger looking than Clive's. (lol, you should see my husband's mouth and jawline.)
Wow, I don't think I've ever heard of Clive Owen described as more feminine than any other man alive!
I loved to hate Baltar, but I always thought of James Callis as a bit boyish:
I met James Callis last year at a live concert of BSG music--really sweet, funny guy. Very naturally charming and witty, kind of self-deprecating. Also pretty short--maybe 5' 5" or so. I thought he was adorable.
When he's really skinny, like in those pics ^^, he kinda reminds me of Prince.
I like Clive Owen, but I don't think the above is a great pic of him. I do like the craggy-handsome look that he and Daniel Craig have going on.