Taken from my own collection, I think these would suffice:
1. Black cap toe oxfords
2. Brown/cognac/burgundy (whatever shade) derby brogues
3. Brown/cognac/burgundy (whatever shade) single monks. These could however easily be exchanged for a number of different shoes, like chukkas, plain toe derbys, various boots of different kinds.
A light brown cap-toe brogue (currently filled by the Grenson Radley in tan)
A darker brown wing-tip (currently filled by the Grenson Headingly in cognac)
A black cap-toe (currently filled by the C&J Bedford)
But then...I need a mid-brown suede cap-toe as well, and/or a penny loafer, for wearing with jeans...so sticking to only 3 is difficult...