I'm only posting this because I just spent more than an hour looking for the perfect name for Polish nun in my current novel. Some of you might want to give these considerations some thought when you go shopping for names.
One of the first signals you send to the reader is the name you select for each character. A character named O'Malley is different from the same character named Nguyen Van Thi. Shop for names and keep a journal full of them. You never know when you will need a convincing, dashing fighter pilot. Naming him Dirk Cameron just might fit what you are writing. At least it might be more convincing than Warren Stimpler Jr.
Naming characters is an important step. Take the names you are considering to someone you trust and ask him to tell you what each name implies. You will find some surprises. You see, you already know who you are giving the names to. Your confidant doesn't know the characters yet. He or she just knows the clues that come to mind from the names you offer.
New novelists too often overlook this. You can spot it in novels where characters' names conflict with their lives, biographical data, and ethnicity. You will also see novels where several characters appear to have names that are very similar and even begin with the same letters. This is a confusion factor for the reader.
Now, having said all that, don't fall in love with names. It seems to be some strange law of publishing that the more you love a name, the more likely the attorneys at the publishing house are going to tell you that name has to go for legal reasons that never make any sense to you. Think about backup names for your most important characters.