I too think towncars are a better deal than the cabs. Most towncar companies will run about $120 or so round-trip including tip. A major bonus of going this route is that if you want, you can stop at a grocery store and stock up on bottled water, soda, and snacks to keep in your room. That will save you time and money durring your trip!
Another option is Mears for around $20 per person. I would avoid this unless you're
budget won't allow for anything else. It can take a LONG time to get to your hotel, between waiting for a bus/van to take you and all the hotels you stop at before you get to yours (unless you're REALLY lucky and you're the first stop).
Magical Express is a new service Disney is offering, and this year it's offered free to those staying at a WDW resort. You have the same problem as Mears, you may make multiple stops before you get to your hotel, but they will only stop at WDW hotels, and they do handle your bags for you. The downside to the baggage handeling is that it can take hours for them to get the bags to your room.
Personaly, I always get a towncar and have the bell hop help with bags if needed. With all the money I spend, another 120 bucks isn't a big deal, and it's worth it to be walking into the lobby of my resort less than an hour after landing at Orlando.