Punki,
I worked in Munich for a month last February. I fell in love with it, it's one of my favorite cities. I went and visited again during the summer for fun during a Europe trek. All of the above mentioned treks are worth it, and I'll add Rothenburg on der Trauber - a great little medieval town. Don't forget to buy a schneeball to eat, you won't be able to miss them in the local bakeries!

For the neighborhood trains (S-Bahn) you should buy a strip ticket (karte) that has ten places to stamp it. You actually stamp the ticket at the station you get on the train at (you will see others stamping their tickets) every SECOND spot, so the ticket is good for five one way trips. It's also good on the U-Bahn (subways).

If you do happen to be driving from the airport to the convention center, just follow the "Messe/ICM" signs on the autobahn.