I second the Budvar. This is actually the Original Budweiser recipe from the Czech Republic. It is formerly known as Budweis until Anheuser-Busch made them change it.
Also try Staropramen, Pilsner Urquell (First Pilsner ever made), Kastrel (light and Dark), Frankenmuth German style Pilsner is good too.
Guiness is always good. I love Black and Tans. I have also had Guiness mixed with Woodchuck Cider. That was tasty.