I once heard that the fact that minhag olam is to call the day lag BAomer is a proof that the correct way to count each night is LAomer. After all, we know that if one says the number of the day before counting, he can no longer count with a bracha. So can one say, before counting, tonight is LagBaOmer? Only if the PROPER way to count is LAomer. Then, by saying LagBaOmer, he will not have properly counted and can then still count with a bracha. Therefore, since the proper way to count is LAomer, the minhag arose to call the day Lag BAomer so as to avoid such a problem. (Yes, this probably belongs on the Purim Torah thread….)
My personal minhag each night is to count twice (I say the bracha only once.). I say HaYom Yom Echad LaOmer. HaYom Yom Echad BaOmer. I know that, in truth, one is yotzei either way, but for two extra seconds each night, why not be yotzai both shitos?