Hikaru no Go is fun - a teenage boy possessed by the spirit of a (rather camp) 1000 year old Go master. xxxHolic by Clamp is exceedingly pretty with its Aubrey Beardsley style art and lashings of subtext-- sort of like Legal Drug but with actual plot. Petshop of Horrors is about a supernatural, lipstick wearing count and the cop who wants him to arrest him- it's really quite creepy and also has the lashings of subtext.

I'd also definitely second Qwan and Antique Bakery.