tendulkar's 100 centuries… dont ever think that would be beaten
murali's test wickets as well maybe
I think both will be broken - more so Murali's.
Athletes become more professional in their preparations year on year, as a result I can see careers spanning longer periods. It will get to a point where players are playing a few years longer than anyone before them.
Not sure there is a current player who is going to get close to either record, but someone will break onto the scene soon enough and play test cricket for over 20 years.
Tendulkar's record is definitely the one most out of reach. It is a remarkable feat that will require a special player. Tendulkar himself has played test cricket for over 20 years.