So, people are being jerks about it, but October is a good name. I like it. I would spell it Oktober, though, but I can understand why someone wouldn't.
I think October Sky is a nice name, but it's also the title of a movie...if you're okay with that, go ahead :)
Overall, I think October sounds best with a single-syllable middle name, like Anne or Lynn. Also, I would steer away from other names that are also nouns - I saw that October Rose had been suggested - because it sounds too theme-y.
And please, for heaven's sake, please don't name her October November, October Autumn, October May, or any other season/month. Just don't.