Vanilla and peppermint. Seriously, I make stuff in "manly" scents and the guys all go for the vanilla and the peppermint.
I also did a lime + bay rum blend that was wonderful. I think it's 4 parts lime (in my case I used Lime Blossom FO) and 1 part Bay Rum. I tried to do a swirl and left half the soap uncolored and the other half bright green, but the Bay Rum discolored the soap so it looks a little odd now.
These are the main manly scents that the menfolk in my sphere of influence really like:
-Paradise (Daystar)- an effervescent lime scent
-Salty Sailor (Daystar)- a salty sea air fragrance
-Santa's Pipe (SweetCakes)- smells just like cherry tobacco
-Old Spice Classic- (Oregon Trails)- smells just like the real deal to my nose
-The Perfect Man (NaturesGarden)- smells like a very manly grapefruit
-Montego Bay (Oregon Trails)- smells exactly like the real Bay Racemosa EO to my nose
-Barbershop 1920's (Rustic Escentuals)- hubby says it smells just like his dad after a shave at the barbershop. It brought back a lot of memories for him.
-Twilight Woods (Peak's)- a pleasant woodsy scent with a slight vanilla undertone to my nose
-Soapy Clean (Brambleberry)- smells just like Tone soap.
-Sugared Spruce (WSP)- smells just like you'd imagine it would smell like. Very aptly named.
-Cedar & Saffron (Brambleberry)- doesn't smell like cedar or saffron to my nose, but it does smell quite lovely- it reminds me of the smells of Christmas.
There's more I could mention, I'm sure, but those are the biggies.
For me Fragrance oil aren't as popular with men, men seem to prefer the essential oils peppermint, patchouli, tea tree, pines, cedars and men seen to be into exfoliants much more then women. But pick are also pickier, the want my bars with a 45 degree chamfer around the whole bars because it's it's sharp. I've never had a woman complain about that but numerous men have.