a few favorites of mine:

color(s): red, black, blue, white, pink(depending on the shade)



ice cream: chocolate 



animal: undecided among these: cats, dogs, horses, dolphins, wolves, eagles, swans, doves. 
fictional/mythological: unicorns, pegasi, dragons, phoenixes. 



car: don't have one



day of the week: any day I have off from work




season: spring(after a bit of thought)





holiday: Christmas




candy: pocky, among a few others.