I refuse to "pay-to-play" any single game... Including World of Warcraft.
I am willing to pay for a network (XBox Live, PSN, etc.)... Additional content is fine... But not a monthly subscription that forces me to play the same game over and over. I think that model is broken and if gamers buy into it there will only be a few development companies left in the end because people will not pay for anymore then a couple of monthly subscriptions to play games.