Dark and Light is due to be released soon. It is a fantasy mmorpg similiar to WoW, and is suppose to have the largest size landmass in any mmorpg game. Has multiple character classes, weapons, and quests. Supports flying mounts where you can fly across the landscape and explore. You aren't likely to get bored of it soon due to its size.
I, too have both. The best thing about GW is the mapping. You don't have to find a city find a flight route, talk to this guy talk to the other. You pick a town you've been to and you can "map" or teleport there. The level cap is fairly low at 20, but there's so much to do even at that level. The world is huge. I enjoy soloing to find towns and loot. Something that's harder to do in WoW. You can use NPC's to fight with you instead of waiting for people to join a party. The biggest thing that dissapoints me is the action/spell limit. You only have numbers 1-8 for actions and spells. Unlike WoW, where you can have almost all on screen.
I think the best thing about WoW is the creation of items. You can make stuff to sell. Other than drops, there's not much else you can sell in GW. Not to say it's harder to get money, but the gold is just worth more.
I prefer GW to WoW most of all due to NO MONTHLY FEE. You don't have to keep shelling out money to play the game. Thing about it, 15 a month for 12 months = $180 a year. No thanks. To have to put up with laggy servers and a servre queue, that could take half an hour to join. Not to mention having to create a character on a specific server just to play with friends. GW your char is on any server you pick.
They both have their attractions, but I believe it's the better marketing campaign that's put Blizzard on top. GW is definitely worth looking into.