LTE is going to be a data service only, still uses the existing network to place calls.

Verizon is launching 25 LTE networks by November and then will roll it out to other places after that. For devices they will start with air cards and then maybe will have phones at some point. I'd say at least a year until then. So no, buying a non-LTE phone for use on Verizon now will not make it obsolete.

Plenty of folks here in Madison bought an Evo even though we're not scheduled to get Sprint 4G coverage any time soon. They use it on the 3G network just fine.

Also another android phone that will be out on all the carriers is the Samsung Galaxy S, which for some reason needs a different name on each carrier. AT&T Captivate, Verizon Fascinate, T-Mobile Vibrant and the Sprint Epic 4G (which gains a side-sliding QWERTY and 4G).

http://www.androidcentral.com/samsung-galaxy-s-event