Sub Sites or Two separate domains?

I have a client that wants two distinct sites. One that is all about his football career and the other that is about his acting career. He wants to be able to give people his main domain name and when entered to be taken to a splash page that gives the vistor the option of going to either site they choose. My question is: Should I just use one domain name and create sub sites with it i.e. "acting.XXXXX dot com" and "football.XXXXX dot com" with the splash page being "XXXXX dot com"? Or should I suggest two separate domains i.e. "johndoefootball dot com" and "johndoeacting dot com" with "XXXXX dot com" as the splash?