Definition...hmmm...
Yes, to say your ultimate daily driver is quite hard, because its not just that a car gets from a-b perfectly and without any fuss or hassle, because if that was the case, we would all drive Toyota Corolla's. However, the Corolla is not cool, fun, fantastic, and definitely not the ''ultimate'' in anything...and that is the essence of an ''ultimate'' in anything - it doesn't mean that it woks well - it doesn't mean that it is fuel efficient. It means that that one or number of cars is what you would want to drive everyday - not because everybody has one - not because you need shopping space, (because, well, if you can afford any one of these suggestions, i think you could probably afford to shop online... :D), it's because YOU like it.
So, whatever car you put, you can't be wrong, because it's your choice.
(unless its a Toyota Corolla :D)