I own a "Abus Granit 51 Plus" lock and I really like it. The "EaZy KF" bracket attach to the seat tube and holds the lock very securely and away from my legs. The lock also came with LED light key holder and a "key card" which makes it possible to order a new key or another lock with the same key.
On the downside, it's heavy, but no bike thief would even try breaking this lock without an angle grinder.