In Pilzn, you need to try the Pilsner Urquell, possibly the best beer of its kind in the world. And keep an eye out for something called 'Budvar'. This is the real Budweiser. Also a Czech product.
And if by some miracle you see any Groenwohlder being sold in Munich, try that too. It's from northern Germany and is very North German in character, but it is astonishingly good, even if the Bavarians turn their noses up at it.
Last, but not least, Bayern is the home of Hefeweizen. The classic is Schneider Weisse Original. Try some of that too.