I don't typically play games with a monthly fee but EVE let's you pay for a year in advance if you so choose. I do this at income-tax time every year which is great for me, personally. I've not found another MMO that does this yet, that could also keep my interest beyond the trial period or three months at the most.
In the past, it was hard to find a retailer that sold time cards but I think they've gotten better about it in the last couple years.
Age of Conan lets you pay for a year and it becomes a lot cheaper.