I used to have around ten maybe eleven MTW folders. Each however big they normally are. All of which were modded in one way or another, even my supposed 'vanilla' version. You've got Samurai Warlords, Hellenic - Total War, Fall of Rome, MedMod, XL, BKB's Super Mod, Middle Earth Total War for MTW, Silmarillion - Total War and as you say P&M. And don't forget Napoleonic - TW. The list goes on.

All however were wiped clean in the Great Re-Formatting of 2004, or was it '03, I've forgotten. But my point is still there, many good mods, all of which are equal, but some are more equal than others. ^_^
Now I only stick to Samurai Warlords.