Guerlain: Derby. As classically masculine as it gets: citrus, woods, a touch of leather. (Of course, I find most other vintage Guerlains perfect for men as well, from Chamade to L'Heure Bleue.)
Gucci: not a huge fan of the house. Perhaps the incensy one (I always forget which number it is, I or II)
YSL: Kouros. Assertive, musky, dirty, even in the reformulation.