I've gotten really spoiled by Creatures, recently. As far as a-life is concerned, I haven't found anything to top it. I've recently learned how to IQ test my Norns, so I now have a ship full of Norns that are all smart enough to talk to the hand. You just can't beat a virtual pet that laughs, dances about, and tells you it loves you when you pet it (as opposed to one that just doesn't die if you care for it properly).