Get a straight axe for your first one. Curved axes are for more technical mountaineering. Length is very much a personal preference and is based on your height - I'd suggest a 60cm to 70cm for your first axe, depending on how tall you are. I'm 6' even, and I use a 65cm axe. A comfortable grip is my #1 priority. You're going to be holding onto an axe for a long time, so get something that fits nice in your hand. These BD axes are great. I've got the regular Raven, and it's nice and comfy. #2 is weight - hogging a heavy axe sucks. On the same token, an axe that is too light doesn't really give me much confidence if in a situation where I have to self-arrest or belay off it.