I also agree with the Moly. And also that any grease is better than no grease, BUT...lithium base with no moly will do just fine. Just never use a calcium based grease for anything.
Grease is old when the oil starts to seperate from the soap base. Ever opened a can of grease and see oil on top? That is the seperation I'm reffering to.
Shell is a highly touted grease, BUT I have seen Shell Alvania seperate in a matter of a few weeks, so I don't much care for it.
Mobil and Castrol have very good greases IMHO. I like Castrol 860-220 for a lith with some moly, and Mobil 1 synthetic is a good grease with good resitance to water and a high load rating. The mobil 1 synthetic is also compatible with lithium based greases.