Wherever you go you will not see it all, Wherever you go it will be beautiful. Make sure you see the Charles bridge, and walk up to the castle and DEFINATLEY go into the cathredal - totallly stunning, DP says it was the first time I was lost for words.
The beggars, made me feel really bad but they are everywhere, be prepared. I was shocked at the graffitti in places.
The Jewish quarter is also lovely, good for a moring stroll.
I would try not to eat on the Main square (sorry Aimsmum) the further we got away, the cheaper and better the food got!
And go to the Sex Museum - good fun!
We also went in the deep midwinter and it was freezing, but beautifully set in snow.
Am really looking forward to the break now. We had 2 Belarussian children staying with us for the past 3 weeks - they went home tonight, so I am totally exhausted and really in need of a break. I want to have a good idea of some places to definitely see so as not to waste the time - its only 3 days. Must have a look out for the sex museum