I like the tags.
It depends on how happy you are with your iPhone 3G, how much you want a new phone, whether you are in the city center of San Francisco, and how much you really want the new 4G/LTE data speeds.
I think there will be an LTE phone out a lot sooner than next summer. I would guess that they will have a marqee Android or iPhone handset ready to go when they unveil new LTE/4G network later this year or early next year. I can't imagine that they will launch service and not have some really cool phone ready to tie into it.
Still, LTE/4G is just faster data and service is likely to be concentrated in only the city centers initially and Verizon has a great reputation for reliability but it seems unlikely that the launch will go perfectly, so there will likely be initial issues. If you aren't too upset about 3G data rates, there's no need to wait. There's nothing really magic about LTE.
If you want to wait, I would make an educated guess than between mid-Nov. and late Jan. Verizon will have a big event where they talk about how they have the most advanced network in the world and they will have some amazing 4G Super Droid or iPhone for you to use on it.
On the other hand, the new Droid X is pretty awesome too and you can get it now and the service is pretty rock-solid. It depends on how much you really want a new phone.