For the votes: BUY.
To take in consideration:
-Offer the software in buying model with 12 months support that include updates (for example 120€).
-After that, offer a renewal for 12 more months support and updates at lower price (for example 60€).
-The people that they doesn't the renewal, lose support and updates, BUT THEY COULD STILL USE C3.
-PLEASE, PLEASE, PLEASE, support Firefox or Opera ASAP.
The owners can take a percentage of the profits to avoid all the people only pay for the first year (probably the case of most hobbiest).
I think would be good for everyone...
P.D.2: sorry for my poor english but it's late ;D