I've just called into the newly renovated National Museum on Wenceslas Square, where I've discover that they are offering a new multi-day multiple entrance ticket.
The ticket costs 260czk and includes one admission to each of the following museums over a five day period:
Historical Building of the National Museum
New Building of the National Museum - recently renovated and utterly spectacular
Ethnographic Museum of the National Museum
National Memorial of the Vítkov Hill - well worth a trip, if just for the city views alone.
Lapidarium of the National Museum - a fascinating look at some of the city's old statuary, including the original statues from Charles Bridge
Czech Museum of Music - an odd spot, full of instruments that didn't quite make it into the orchestra
Antonín Dvořák Museum
Bedřich Smetana Museum
This ticket represents great value and encourages visitors to explore museums that they may not otherwise see.