Ask them about Symbian.
Symbian is by far the most popular smartphone platform, but it's not a household name. It's just an OS - my mom doesn't even know she needs one on her phone
As pointed out by other readers Symbian ISN'T the brand that Nokia holds up to their end users. I think it's a mistake to advertise Android to the masses as a brand. Sun tried that with Java and it didn't work because they spent so much of their resources advertising Java to the end user they didn't actually do compelling things with it. Contrast that with Flash where Adobe did compelling things with it, developers wanted to do that, and users loved it. First doing something compelling to attract attention, then you can tell them how you did it. Not the other way around.
You have a choice in the US between AT&T and T-Mobile, and Rogers now in Canada as well. It's coming soon to Vodafone and Verizon as well. Carrier choice is coming.
I'd add lack of customer support as well. I'd be willing to go with the Nexus One, but I know Google has a really poor history for customer service across all their products/services. Until they learn to provide this I'll still buy through the normal channels.
So you downvoted me because you did not like my opinion.
The thing with Customer Service is that when you don't need it, sure everything is fine. When you do need it, you want to be sure it's there. My problem is, with Google you can't be sure. And that could be problems with ordering the phone, warranty service, or whatever other unforeseen problem comes about.
Look at Google's history, and with whatever product they offer, be it Gmail, Apps, AdSense, Adwords, and you easily find the Customer Service complaints. For buying a phone, I have a choice. For Adsense/Adwords, not so much.
If you did a real survey asking what 'Android' or 'Nexus One' are, I'd be curious to know how many knew (I'm guessing about 10%)