Get both, definatly both. I tend to bike 3 days of the week and ride my scoot the other 2. The scooter is just as fun as the bike, and it's nice to have a non-car option when you're tired or you've managed to over-sleep. I would reccommend that if you do decide to get a scooter, purchase it from a real person in a real store. I bought mine online almost 3 months ago and I'm still trying to get all the legal paperwork for it completed

As far as operational costs, I've been tracking my fuel consumption pretty closely with car vs. scoot vs. bike and while the scooter does save me about $0.10 per mile (fuel consumption only), it's not likely to pay for itself any time soon.

Again, get both... options are always fun!