There are 50 odd countries in Europe, all with their own language, culture, historic sites etc and you want us to tell you the best place to visit! Surely, if you are interested in Europe, you must have some ideas of what you want to see, and there must be some countries that attract you. I suggest you get a tourist guidebook to Europe and try to find a place that interests you.
It really depends on what you're interested in. Rather than coming on here and asking such an open question, why don't you go to the travel section in your local library and start reading up on some of the different countries in Europe and what's there to see and to do, and once you have an idea, then come back with more specific questions.
What's best for you depends on your interests and expectations. In my experience, it's hard to go wrong no matter where you choose to go. There are interesting things to see and do,, good food and nice people just about everywhere. If you're looking for beaches, try places like Sicily, Sardinia, the coasts of Portugal or Spain or the Greek islands. For scenic beauty, you might like the Netherlands with the tulips in bloom, Cinque Terre or the Amalfi coast in Italy, or the Bavarian Alps. For a city break try London, Paris, Barcelona, Prague, Budapest, Copenhagen ... There are castles and historic sites all over Europe.
The Spaniards are soo friendly. London has amazing nightlife, Spain best food and people, Rome has ancient sites but too much pizza/pasta no diversity in food, Paris is mostly for couples it's so romantic. Overall, I would say Spain. It's so important when people make you feel welcomed.
Italy. If you go, be sure to visit Florence and Rome. Both cities are beautiful and filled with culture and history. Also there are amazing beaches on the Amalfi coast.
Deutschland
The most beautiful city are Paris! Also whole France is very pretty and interesting. Then Nordic and Baltic countries are great too!
Dallas.
Malta
There are so many to choose from, but I love life here in Marbella, Spain :)