Hradcany is the area that contains some of the most fascinating tourist sites in Prague. Here you will find first and foremost Prague Castle with St. Vitus Cathedral. This should be either 1st or 2nd on your list of sites to see while visiting Prague. If you intend to miss them, then why are you coming to Prague? On the grounds of the castle you will find St. George's Basilica (Bazilika svatého Jiří), Lobkowicz Palace (Lobkowiczký palác), Golden Lane (Zlatá ulička), and a number of galleries. North of Prague Castle are the Royal Gardens (Královská zahrada) and Queen Anne's Summer Palace (Letohrádek královny Anny). East of the castle area you will find other notable sites like the Hradcany Square (Hradčanské náměstí), Loreto Sanctuary (Loreta Praha), Strahov Monastery, and more galleries.
Finding a place to eat or have a drink isn't an issue. I recommend trying local places. You can always get McDonald's or Starbucks back home. ;) Be expected pay more in this area to eat. I think you will understand why.
If you have the time and money then go to everything that interests you, but in my opinion you shouldn't miss the following, Prague Castle (take a tour to see all that's possible), St. Vitus Cathedral (pay to enter all the parts), Strahov Monastery, and then anything else that would interest you. Regarding the Golden Lane, to me this is probably the most over-rated site of them all. You have to pay to walk down this small little street to see things that you can see elsewhere. To me its not worth it, but judge that for yourself.
Bordering Hradcany are the areas of Mala Strana, Petrin, and Letna, that contain many interesting sites in themselves. Hradcany is just one part of Prague, but probably the most important reason why you come to visit in the first place.