If you were to get just one set of gear for both pve and PVP, which would you get. I have no desire to raid, so do not need to be geared beyond flashpoint level.

For someone like me which would be best? Can full PVP gear function to an acceptable level in flash point tanking? Can pve gear (66, 69) function to an acceptable level in PVP? ( no intention to do ranked)

I used to carry 3 sets of gear prior to 2.0 -- PVE tanking, PVE dps, and PVP dps (with shield generator).

I think either will do, as long as you aren't looking to be performing at your best in "the other" environment -- which, since you are posting this in the Tanking forum, might mean that you would struggle on some bosses with less well geared healers in PVP gear.