I swear by heavy dumbell pullovers for lats...in fact awesome total upperbody exercise.
Bent-Arms with deep breath,get a good stretch in the lats,exhale while pulling to just over the face/chest area, and repeat.
I do them every week,at times as heavy as 5 reps and at others up to 20 reps.........standard is 8-12 for me pyramiding up in weight as I decrease reps.
Yup! Been a back mainstay of mine since I was 15 or so. I have a damn good back and this exercise has always been one of my favorites. I use them to pre-exaust lats. The machine can be more effective but few gyms have them. In the bay area for example only the Golds in Mountain View has one. Otherwise, I stick with dumbells.