I'd combine names and make up names, sci-fi sounding names like Hysy Sigee and silly names like Constance Prattle.
I bought a baby name book and used that to name characters, but then I discovered the Social Security Administration's list of baby names. It is nirvana for name nerds like me, especially if your novel takes place in the United States.
The SSA released the data for 2012 this week and while the big news is usually the most popular names (Jacob and Sophia), there is a cornucopia of name goodness throughout the website.
First of all, the database goes back to 1880, when the most popular names were John and Mary. And you can find the most popular names up to the 1,000th (Layton and Eula in 1880; Dangelo and Katalina in 2012).
You can also find the most popular names by decade. I write contemporary YA, so my characters would have born in the 1990's. I can see that Michael and Jessica were the most popular names during the era of grunge.
If you want to get specific by geography, you can also check most popular name by state, up to the 100th(ish) most popular. Say I have a character born in Alabama in 1997. The most popular names were William and Hannah. Colby and Sabrina were 100th. Nationally, William was 19th for that year and Hannah was at 5th. Colby was at 229th and Sabrina 53rd.
If those kid were born in Texas instead, the most popular were Jose and Ashley. The 100th were Joel and Angela. Nationally, Jose was 32nd and Ashley was 3rd. Joel was 126th and Angela was 93rd.
Of course, there are other things to consider when naming a character. Such as the sound, the meaning, the connotations of a name. But if you're writing historical or contemporary fiction, then the Social Security baby name database is an incredible source of information to help you make the best naming choice.
And if you're looking for a last name, you might want to check out the genealogy data from the U.S. Census. It has data of the most common surnames from the 1990 and 2000 censuses.