I think most people are just performance nazi's and would pay anything for that tiny extra bit of performance. The rest just follow the herd and have never even tried it. People said i'd need boosters for a very long run when I wired the building I work at but in my tests there was only a TINY performance difference, even at 400ft with unshielded cat6 cable... Cat6 is only rated to 330ft... I did end up using a switch but only because it would have been very expensive to run 15+ cables 400+ feet to the other end of the warehouse.
Standard coax that you buy in the store is capable of 200m (650ft+) and the ticker stuff is almost 3x that. The cat6 cables will not affect the coax because coax is always shielded.
Your best bet will be to run another coax, or buy that balun and use your cat6 cable. Don't buy a booster until you know you need one. Then just buy something like this:
http://www.amazon.com/Motorola-Boost.../dp/B000066E6Y
Sources:
http://fcit.usf.edu/network/chap4/chap4.htm
http://en.wikipedia.org/wiki/Category_6_cable
http://en.wikipedia.org/wiki/Coaxial_cable