ANY good OG Kush would do. I got a pack of SinSity LVBK on recommendation from a few people, intended for relief of arthritis pain and word is this is an instant good night's sleep, unfortunately I haven't even seen a bud yet so can't say much about it.
A friend in the UK swears by William's Wonder from SickMeds seeds, he's been toking since before I was born and if he says it's the best he's ever had I believe him, he's got a nasty spine injury from coming off a motorcycle in India so he's also a medical user. He's the hardest-to-please toker I know, I've seen him wrap some Skunk in a skin he'd just coated with honey oil and smoke the whole damn blunt himself and not even get red eyes. He said he can't finish a joint of it so it's got to be excellent.
But in general I go for anything Kush works fine for me, pretty hard to mess it up and always strong no matter who the breeder, yields go from average to iffy but I don't grow commercially so I don't really care too much about yield, I get a little that's fine, I get a lot even better because out come the bubble bags