Emu XL-7 & MP-7 User's Group

Hello there,
I was thinking about picking up a good "bread and butter" ROM (ie: 
filled with regular instruments such as pianos, guitars, organs, 
acoustic drums, etc.), probably from eBay (seeing has how they're 
getting hard to find in stores). What, in your opinion, is the best 
ROM for realistic sounding pop instruments from the following:

1) Sounds of the ZR
2) Proteus Pop ROM
3) Protozoa

Any help would be greatly appreciated!
Fab