The names of my sims mostly reflect what I´m reading at the moment. That´s how I come up with names like "Randolph". Even though english isn´t my first language, I tend to stick to english names (with a few exceptions).
I started playing around Christmas, so my first sim is named Holly Winters. Her children are Chris and Yuki (snow in japanese).
Sometimes I try to stick to a theme - most of my fairies have "plant" names, like Rowan or Willow.
In one of my saves, all sims are named after flowers.
All of my aliens are named after the actors who played Vulcans in Star Trek, my first alien baby was named Leonard, after Leonard Nimoy.
My first vampire is named Benedict Giles, Benedict because I watched Sherlock at that time and Giles after Rupert Giles from Buffy. It seemed funny. :p
I also browse sites for baby names a lot.
Also, I never change game-given names - one of my time machine children is named "Uhlbert". He seems to cope.