Actually this is true. I stand corrected from my earlier statement. To keep our "grandfathered" unlimited data, Verizon states that: "
Customers who purchase phones at full retail price and are on an unlimited smartphone data plan will be able to keep that plan."
So, our only option going forward is to buy at full retail. This choice is going to depend on each user. If you're the type to use a ton of data (10gb+) per month, it would probably be smarter to buy at full retail and keep your unlimited. If you don't use that much, tiered data probably isn't a bad idea along with a subsidized phone.
Personally, I'd rather not give Verizon additional money. I'll either a) buy from an external vendor (i.e. Amazon, Wirefly, ebay, etc) or b) buy directly from Google and become a GSM customer.
To OriginalDroid, while I hope I'm wrong, it's my understanding that Verizon's LTE bands are significantly different from what other carriers are using. In a year or two, things could change, but for this round of Nexus devices, Google is only going to be making GSM versions because they can't make CDMA (for Verizon or Sprint) version independently on their own.