I can't decide between Pilot and ANNET... but I'll go with ANNET because while Pilot may be more deserving of the love, ANNET certainly gets less of it. Poor little Annie. I'll bet she hasn't gotten to talk to her sister over at Aperture in forever.
Zee Captain can never have too much love. Pilot loves Zee Captain. ANNET loves Engi (I think ) but she has no emotions since she is an AI. Skalky loves Zee Captain as much as Pilot does. Leaving Snippy to be forever alone