Uncertain. I'd like to unsub on principle, but there are so many other things to do in WoW besides raiding for some players. Since my guild took a holiday break through December, I've fallen into a Battle Pet collecting spree. I still need to work on Arch as well, for the nifty toys to be found there, though I get burnt out on that pretty quickly. There are easy achievements to chase, having missed them almost purely due to forgetting that they're time sensitive, as well as slightly less easy but still pretty simple achievements I've simply let slide because other stuff seemed more interesting.
It depends on what's caught my interest, come May. If the launch date is announced and pushed back til autumn, I will be sorely disappointed in Blizzard (wtf did they roll out patches so regularly if they couldn't tie it all up at the end with similar speed?) but the other things occupying my time in WoW may keep me paying up.
(I was going to put in something here about something Blizzard could do that would both keep me subscribed to the game, as well as continue playing the game, relating to server transfers and subscription times, because I'm in a mood... but that's off topic)