My vote is for $200 (I'm thinking in AUD, but you can call it roughly equivalent in USD).
On the surface, that seems like a lot of money - but I figure it isn't. If you were to pay $15 a month to subscribe to another game, in 12 months, you have spent $180 (and that assumes you paid nothing for the game to begin with, which is most likely not the case). With all debates about whether a subscription fee for an online game is fair or justifiable left aside - I personally consider $15 a month to be very cheap entertainment. If I were to play about 4 evenings a week (which is about average), and discount playing during the day on weekends (which I do, but let's leave that aside), at $15 per month, over 4 weeks, I am spending a little less than $1.00 for an evenings entertainment (and have my weekend time thrown in free).
I would honestly have to challenge anyone to arrive at a better deal.
With this game, you buy once, and pay no subscription fee. On the surface, with all that I know about this game, I can easily forsee myself playing in 12 months at the very least, and much more likely playing for several years to come.
On that basis, a $200 initial spend for any version of the game is consistent with the incredibly good value for money "yardstick" I outlined above. Hence, I have no qualms in paying $200 or more for the CE.