First of all, I know this has been done to death, so sorry!!
DH and I already have a Dd and have found out from our 20 week scan that we are having a DS this time
We both wrote our own separate lists of names we liked, swapped lists, crossed the ones off the we really didn't like and then put the remaining names together into one final list.
My DM looked at the list on Sunday, and had a less than enthusiastic reaction
None of the names on the list are particularly "out there" or "yoounique" (think: Jacob, Rhys, Caleb).
She made it very clear that none of the names we liked were suitable, or "right" for her grandson 
I said in the politest way possible, that it doesn't matter if my mother likes the name we choose, as long as DH and I like it. AIBU to think that I am right in saying that?!
DM seems to think I am being wholly unreasonable, and she should be able to have her say in the baby's name 