I used a Third Eye bar-end mirror for almost a year. Worked excellent in all conditions, but a tad bit small.
When I changed my bars to a set with less rise, I couldn't see out of it anymore due to my big ol paws being in the way. On went 2 of these:
That Cateye road mirror does the job great, but it's susceptible to moving when you fight nasty headwinds while traveling over ~25MPH.