2 monoblocks I believe is preferrable because each channel gets it's own power supply, and a sudden drain on one channel won't effect the other by modulating the power supply. Of course, this is less of an issue when playing typical program material that has a lot of common signal between the channels. There is also less chance of crosstalk with 2 seperate amps.

The only downside I can think of is 2 mono amps might cost more.

[This message has been edited by soundhound (edited November 26, 2002).]