Check it out. They've got a nice client that streams content to you so the up-front download isn't so monstrous. Just choose to use to the turbine download manager instead of doing the bulk download.
It took me less than 15 minutes to download enough content to start playing. Really smooth.
You can play forever for free. There are a couple of races and classes that you can buy access to with real money. There's also more content that you can buy if you want. But playing forever for free is feasible if you don't mind slight inconvenience. From what I've seen in the DDO store, it's not even too expensive to buy stuff that might be worth it in game. I would actually consider buying some of the potions to speed up levelling and the like--for a reasonable price, I will buy items in a game that I find fun to support its operation.
The gameplay is not your typical MMO fare. It's more like Guild Wars, but with a longer levelling curve, multiclassing, and more D&D-like mechanics. The game isn't a faithful conversion of D&D to the PC, though. It takes liberties fitting D&D rules into an MMO-like environment and I think it does sufficient job of it. Quests are all instanced multistage encounters in all kinds of environments. The content in this game is nowhere near as trivial and boring as most MMO content is, and that's just itnroductory/level 1 content.
Usually I'm bored out of my mind in the early levels, but with DDO, I find myself wanting to log back on. That's a great sign from me, someone who is very skeptical, almost outright hostile, towards almost every MMO that he's played.
So please give the game a try and join me: Sarlona server, my character is a Paladin named Beside Always.