Personally, villians are MUCH more fun to write lines for. There's always a certain amount of fun that you have when you write the evil villian's I'm-about-to-try-and-kick-you-lousy-goodguy's-rear speal. Also, you can always picture them sitting in a high-backed chair with their fingertips forming a steeple...
But random people are fun to write in, too, because they are oftentimes the comic relief because no one cares if they suddenly die or say something absolutely off topic. I once had a random guy named Bill in a story, he was an ice rink cleaner, and he rode that big ice cleaner thing that resembles a sit-on lawn mower. He had no lines, but once he saw that other people were in the room, he put his ice cleaner in full gear and raced into the ice rink wall with a tremendous explosion. Then you just go on with the plot as if nothing happened.
There's my two cents.