I went to my LBS and tried on a Bell Influx. The medium was totally comfy, and $65. Just because I like to at least check, I came home and checked online. Nashbar has one a couple years old version(exact same helmet) for $32. Now I like to support my LBS and get parts from them fairly often, but even with shipping that's paying an extra $25 for the same helmet. I'm young and poor. So now I'm going to just go online and get the best helmet I can for ~$50.
My main concern is comfort, then ventilation.