Well, the first question is "which Paganism?"

Let's take a single European country: England. England's history and culture have been affected by 3 entirely different Pagan religions. First, we have the "original" Celtic religions. This is probably the one that influenced England (not that it was called England then) the least, but it's difficult to tell as it's also the one we know least about. You'll notice I said Celtic religions: tribes in different parts of England probably worshipped different sets of Gods, though with some cross-over. Then, we have the Roman pagan religion, a rather different beast. Next (with a Christian interregnum) come the Anglo-Saxons with their own, entirely different, Pagan religion.

But wait, there's more! Later, the Vikings turn up and conquer half of England. Their pagan religion is similar, but not identical, to the Anglo-Saxon one (we actually know more about the Viking religion than the Anglo-Saxon one, though a lot of our knowledge of Viking religion comes from things written much later, so their religion may have changed). And then of course, there's neo-Pagans, who have been around since the 19th century (though I'm guessing you don't mean them).

But wait, there's more! Even if they never came to England, Greek pagans and Egyptian pagans were objects of fascination to the British in the Renaissance and during the Empire, and this passed on to other parts of European culture and America. Look at all those Hollywood films about Hercules, Mummies, etc.

This isn't really an answer to your question, but rather giving some background to it, and suggesting that you might find it easier to ask "What lasting effects did Roman Paganism have on European culture" or "What lasting effects did Germanic paganism have on German culture" though even those are very wide questions.