Jaybourne, I'm fairly new to the hobby, so don't put to much stock in my input. From what I understand, bettas do fairly well with smaller, fast moving fish, especially if they have some room to roam. I think neons would do well with a betta, as long as you keep a small school of them (neons). The betta in my tank was kept with other fish at my fish store, so I was fairly sure he had a good temper before I bought him. Good luck! Please let me know if I can help you with anything else.
Coral bandit, you've given me some great advice in other threads. Thanks for the help...I have to give you some of the credit for how well the fish and plants are doing.