Do you even know what a 51% attack is?  Do you know what can be done using it?  Do you know what would happen if a pool tried to do it?

Let's do a mind experiment.  Assume BTC guild, right now, has 60% of all the hashing power.  Now explain to me exactly what they would do in order to pull off a "51% attack", exactly what they would accomplish by doing it and most importantly exactly why they would do it.