Mr. Answer Man says: Let me ask you this: What do you hope to gain by calling?
If you've gone on a date with a guy and he hasn't called you for another, it means he's not interested. Period. And it doesn't matter how well the date went. There's not a guy on the planet who, having plucked up his courage to call you the first time, would somehow chicken out for number two. If this is the case, calling only gets you lots of awkward phone silence and hurt feelings. It's time to move on.
But if he is going to call you, he's going to call you, so why not just chill out? Besides, it's almost guaranteed that he's got some set of rules about how long he's supposed to let it go before he calls you again, and it would be kind to indulge him and see how things play out.
Your chance to win this guy (if that was your intention) was on that first date. Your chances to assert yourself in the relationship can't begin until you've at least gone on a second. And, as has been pointed out by many an ancient sage, the wisest course of action is often doing nothing at all.
(Oh, and no calling "just to say thank you." Make sure to say a meaningful thank you at the end of the first date and then leave it alone.)
Go to the Mr. Answer Man message board to find out what everyone else has to say about post-date etiquette.