I think the answer is "YES" because while the prices will keep coming down, you want to give yourself time to enjoy it. Carpe diem and enjoy your purchase!
Should I buy another flat screen now while they are still relatively cheap?
My current Vizio 65" is either 7 or 8 years old, and it gets a lot of use. Is there an average life span on these? My previous Samsung 70" made it about ten years as I remember. I see that WalMart still has flat screens in that (or around that) size for relatively cheap.