My theme is to follow what you love. Pick the idea that you are so excited about you would do it for free. Meaning if you had to make a money some other way, this is the first thing you would want to do when you got back from work.
Once you know your passion, pursue it relentlessly. And form a business around it. I believe following your dream is the best bet on a successful business.
I feel your pain Sandra, I too suffer from O.M.S. (overactive mind syndrome)
I keep a notebook of ideas and concept I think would be viable-I think I am up to about 3 pages of stuff. I have to discipline myself to narrow them down to the best and most practical choice.