take each of them back home and show them your Wii.
I'm sure that'd give you more than enough things to talk about!
sounds like you're pressured (internally or externally) to make a decision now on which one you are more interested in. There's no law that says that you need to decide now. You've openly said thatyou still dont know them very well, so just play that to your advantage and see them both until you know which one you want to start a relationship with. At least for a few weeks i say.... you may even get some sexing.
Door A has advantages - if it doesnt work, its a clean break because she's a relative stranger
Door B has its disadvantages - friend of a friend that may cause some collateral damage if you went your own way...but dont let that stop you...she seems like a better fit in my opinion.
if its conversation you're concerned about...talk about anything that comes to mind, anything that you find interesting..at least you'll know if she's interested in the same things you are..and just be yourself. The worst thing you could do is put on an act.
good luck with the Wii