Alrighty, so I'm playing a Fighter. At any level (particularly 1st) it pays better for combat to take one level of Barbarian. I get better hitpoints, better saves (than straight fighter), much better skills, and the ability to rage. If I happen to be lightly armoured, I also get fast movement. Barbarian is massively front-loaded, and if one level of another class is that much better for combat purposes (for fighting, y'know, what fighters do), it needs to go.
Sure one level is all I need, but I'm giving up half a feat for all that.
--Seule