Guild Wars has managed to largely hold on to one that's relatively unique. It's clearly not under the subscription-based umbrella, as there's no monthly cost to play. Yet at the same time, it doesn't really fall under the traditional free-to-play model -- the game didn't launch with any sort of item shop, and the current microtransaction shop is more akin to the supplementary shops seen in many subscription games like City of Heroes.
ArenaNet has always been clear about their intended price structure and the intent for the game to support itself with full-priced expansions rather than a monthly fee. While there might be some debate about how sustainable the model is, it's certainly enticing for some players. So today's questions for you: would you play a game that balanced itself on the Guild Wars pricing scheme? If so, what game would be worth a $50 expansion every six months without a monthly cost? Or do you prefer the more prevalent pricing models found elsewhere?