NiMH has memory too, but not as bad as NiCd. We always suggested allowing NiMH to fully discharge time to time, but we never suggested keeping a phone on its base constantly.
Both these types of batteries need to be primed properly - full discharge/recharge the first few cycles. (Not sure about the new pre-charged NiMH, like Eneloop)
Memory builds faster when left in a discharged state.
Cadex machines can be used to reverse memory, to an extent.
I'm speaking from memory from 6 years ago. Hopefully I didn't mess up too much =P
But in general, deep discharges are bad for any electrochemical cell, and should only be done to prevent or forestall something worse.
NiMH cells shouldn't be "topped off" when they're nearly full, but that doesn't mean they should be fully drained before charging.
Fully discharging any battery isn't good for it. NiCd had the particular problem of "memory" developing though, so going through a full discharge cycle was necessary to prevent the memory forming. It wasn't good for the battery, but it was better than letting the memory develop.
I'm not aware of NiMH developing a memory, so that wouldn't be a good thing to do with NiMH either. I always tried to avoid full discharge of my NiMH batteries and always got a pretty long life out of them.
Really the full discharge cycle is an artifact of the needs of one particular chemistry (NiCd) that became something that "everybody knows" you should do long after it became counterproductive.