First, the new DROIDs all come preloaded with the augmented-reality, multiplayer game Ingress. You currently need an invite to access the game, so buying a new DROID is an easy in without knowing somebody playing Ingress. (You also get five Ingress invites with a new DROID purchase.)
I have access to Ingress, and I experimented with it a bit this summer at Google's I/O conference, but honestly, it's not really my thing. If you're a gamer who wants in to Ingress, buying a new DROID will do the trick. Learn more about Ingress here.
Motorola and Verizon are also offering six free months of Google's All Access music-streaming service to people who purchase a new DROID. The service costs $9.99 a month, which means the promo is valued at roughly $60. I don't think All Access would be enough to convince me to buy a new DROID, but it could push me over the edge if I was already teetering.