I stay In Praha for 5 days, which one were really good.
There are lots of wonderful places to see, good drink and food to have.
I especially recommand the Praha' park, with the Black Tower, in which you may have very good sightseeing in sunny days, and have such a drink in the bar not so far....
But, don't forget the Charles'Bridge by day for the architecture, and by night where you will find some good bars and night clubs not so far.
Very good stay.