Well I have a long list
second Kyoya Ida from Jiraishin using guns is not actually "brawn" in my opinion
Speaking of gun, I like Tatsuya from Ouroboros as well, though this one is definitely both brains and brawn type.
This is pretty predictable but I have to repeat Eumenes name again. It's too good of a manga not be mentioned often.
Neuro from Majin Tantei Nougami Neuro being a demon with supernatural power still counts, right?
Who can ever forget Tokuchi from One Outs and Hiruma from Eyeshield 21!!
Then there's Dr. Katou from Iryuu - Team Medical Dragon, not exactly ingenious super intelligent, but she's a doctor who's fighting the corrupted system, one needs quite a brain for that.
I guess mentioning Akiyama from Liar Game is a waste of letters, since everyone in this thread must have him in mind but forgets somewhere in their head

Man is more ape than many of the apes.

The leads from Gunka no Baltzar and Shoukoku no Altair are military strategists.

And of course, Black Jack, the super-surgeon.

The guy in Sakamoto desu ga? can do anything. Anything at all.

[Hopefully nobody is forgetting Ciel from Kuroshitsuji. The cunning little b*stard.]

Don't forget about Lupin III.