Difficutl to answer. What do you like? For a first time it is:
- Viktualienmarkt (but the shops are closed on sunday), Marienplatz with the townhall, various churches before around noon
- Afternoon, BMW Musuem and World or Deutsches Museum or alternatively you visit the Residenz (the place where the Bavarien King did life)
- Evening: Dinner at a traditonal Wirtshaus (alternatively you have dinner at Airbräu at the airport)

Public Transportation is a must, otherwise it will be very complicated to get around town. It is very easy and convient to use and people in general are willing to help if you ask them.