You know my vote!
Actually, you're quite right. Whippets tend to be attention hogs. They'll 'demand' to be petted, and will sulk if they don't get it. Also, like all sight hounds, are more pack dogs, tend to have more separation anxiety if you've only got one. When our last grey passed away, it was really hard on her.
Deerhounds, and all sighthounds are extremely hard on cats. Deerhounds are not terribly healthy, and tend to be a short lived breed. 10 years at the outside, I believe.
Labs are what you make of them. Fit or fat, smart, or stupid. I've never met one that didn't take on the characteristics of its owner. Had one neighbor who was in a car accident and hurt her foot badly. Her yellow lab started to limp - no shit!
Sounds like you've made your decision, can't say I've ever heard of them.