if your looking for sweet mellow pets id say stay away from runer and runner mixes, eve if you spend alot of time with them as babies they still tend to remain very "skittish" birds, its just how they were developed...(so this includes khakis)
Ive heard great things about muscovy, pekin and cayuga for breeds that tend to be realy mellow and good "pet" ducks.
of those id personaly go muscovy or cayuga over pekin.
if your looking for eggs though cant beat runners, khakis and the layer hybirds.
ive currently got 6 runners in the brooder box (almsot 3 weeks old) and i spend 3 hours every day split up into 1 hour blocks with the ducklings...and have since they arrived home as "day olds" and they are still incredibly jumpy and will bolt away from me rather than come neer me. i knew when i got runners that this tends to eb their nature, but i love them and they lay nicely, ive got plenty of snuggly pets...so it works for me lol.