W.N.
I've been starting to research this some as well, as my son is 10 months old and I'm thinking in the next 2-6 months he'll be able to do the back of the bike thing...or the front of the bike. I've decided against the trailer thing, as it seems like a cage and they can't see anything- and they're really expensive. Now, I'm choosing between the seat on the back OR the front of the bike...
I'd be interested in the other responses you get back too:)
-WEndy