I've always liked it - it's not my favourite, but it's classic and uncommon, yet not weird. The usual nn is
Penny, of course, but in a
London newpaper BA last week I saw
Poppy as the name to be used as the nn from the start (with
Penelope as the registered birth name).
Poppy is becoming popular in Britain, but I applaud those parents for giving their baby a sensible name to fall back on!