Another famous bearer would be Lesley Garrett, the famous singer. I think the name is lovely, though for me it's more surname than given name. I've never heard it pronounced with a Gar or Ger, only ever heard of it pronounced Gare-et/Gare-it though, but that be a more British pronunciation.
Actor Garrett Hedlund. Played in movies such as Troy, Four Brothers, Eragon and a little in Georgia Rules. That's all I know so far. I'm surprised no one has mentioned him yet.