A name is an important attribute. Not just for people, but for characters in stories too. When writing fantasy, there are a number of naming options available to a writer. Some of these:
(i) Invent one. The perils of this approach are many. Firstly it may sound stupid. Secondly it may be unreadable. Take some of the names in Iain "M." Banks' The Player of Games: Jernau Morat Gurgeh and Yay Meristinoux. Then we have a machine called Mawhrin-Skel and one called Chamlis Amalk-ney. Yark! (Terry Pratchett satirizes this approach in The Colour of Magic with Lio!rt and K!sdra (or somethings similar)).
(ii) Use a fashionable one. Peril: the possibility of becoming dated. Not a serious consideration for aspiring writers, I suggest. But I wouldn't advise using Olivia or Grace or Ruby, names that are extremely popular today but may not always be so.
(iii) Use a popular classic. Jack will still be popular in one hundred years. It just will. Peril: a sort of blandness, I suppose. A smudging across of all the other Jacks your reader has read about.
(iv) Use a rare classic. In His Dark Materials, Pullman uses the names Will and Lyra. The peril here is of the name potentially being seen as old-fashioned. On the other hand, there is the possibility of setting a trend.
An excellent resource for names is at the Office of National Statistics, where you can download spreadsheets of boys' and girls' names for 2008. The only thing you don't get is any names that were used fewer than three times (to protect confidentiality, apparently). There are more than 7,000 girls' names here and more than 5,000 boys'. So if you're having a baby or naming a character, this is a good place to look. (75 girls were named Lyra in 2008, and there were 202 Wills.)
I already have a name for the main character of my next MS: Edison (which I now see was used 22 times in 2008). But I need a name for the second character, a girl...