On the not-so-cool side of things, you're going to have to buy your electronic monster miniatures and digital terrain. Yes, there will be very boring place-holders if you, like me, are cheap. There have been lots of howls about this. Being cheap, I can understand. But I don't think WotC is that far off-base. After all, their model has to be Magic: The Gathering Online, where you buy your electronic cards to play in the game. People have shown they are willing to shell out real money for virtual goods. Hell, Second Life is predicated on the idea. And there are other reasons to think that it might make sense. Over at RPG.net, Samhaine said:
It's also common in subscription plans that heavy users are actually a losing proposition, since they use a bunch more bandwidth and resources than average users. In this situation, these users are probably the ones most likely to shell out extra for miniatures and terrain. If it works, this will allow WotC to not cap their earning potential from their hardcore users at $10 a month.
So while I, personally think spending real money on such things is a bit silly, if it works for them, great!
That all said, I still think they've stumbled horribly in not building more of a bridge between dead-tree Dragon and Dungeon and D&D Insider. I can certainly understand WotC focusing the vast majority of their attention and resources on the core books of D&D, but I think this is one of those decisions that is going to cost them in the long run. Time, of course, will tell.