Every day I carry a Glock 23 in a Mad Dog Kydex Thumb Break holster or occasionally in a Safariland 3004 holster. If an occasion warrants dressing a certain way, I'll sometimes carry a G26/27 in an Alessi Ankle holster or Eagle Weapons Pack.
For a knife, I usually carry a Mad Dog Mirage X Operator in my right front pocket or an Emerson Commander. I always have my Leatherman PSTII and a Spyderco Experimental II (as a money clip) with me.
I keep a Photon Microlight on my keychain, and typically have a Surefire 3P, 6P, or 6Z readily available.
Blues, unless you want something swinging around and bopping you in the chest every time you move, I'd avoid all but the tiniest of neck knives.