I love love love the name
Luke, alone or as a nickname for
Lucas. I especially like it as a short form for the French pronunciation of
Lucas, which I think is one of the loveliest boys' names out there.
I would consider it fairly popular, it's used commonly in mainstream books, movies and other media (eg,
Luke Skywalker), and I've known maybe two or three Lukes personally in my lifetime. One was named
Lucas, nn
Luke.
For me, it brings to mind a generally good person. Polite and possibly sporty, but probably intelligent. It feels noble, perhaps a little stubborn, but loyal.