Ideally (as Paul mentioned) for road use you want as setting that will lock when you are powering, and unlock when you are off power so the differential does it's job by letting the wheels turn independently.
As for an ATB, pass, I have never used one myself as I have been using plate type LSD's for years with no issues.
PS- BigBubba, it seems you have been a victim of the "off the shelf LSD" myth. Buy a plate type LSD from Burton's and it's sure to make horrible noises when turning corners at low speed due to excessive static preload intended for race cars with big sticky tyres. They need to be setup correctly for their intended use and if that is "fast road", it won't be any noisier than an open diff