For me it was an easy choice. I didn't like Ashley from the start, so she was happily disposed of in that mission.Hmmm...I lost one dude in ME1...I think it was Kaidan. But I'm bringing him back from the dead because even though something about him annoys me, Ashley annoys me more. Also, I don't like the makeover they gave her. Her tomboy-ness was one of the things I liked about her. Plus, bringing people back from the dead makes you feel like God.
Though I agree that Kaidan was kind of annoying as well. I don't think the character was actually the problem. It was just that when I heard his voice I thought of Carth and Carth was a putz!