The design was partially it. He just looked so attractive to me back then. Also, 2007 was when skinny jeans with converse were in, so they did a good job with the outfit. I think my crush on Wilbur is typically why I find tall, lanky dark-haired men attractive.
As for the character, he had a nice voice and was very expressive and confident (things that I lacked). So that's what attracted me to him.