with your lighting your pretty much limited to exotic LPS and zoo's. A few nice (and expensive) ones are blasto wells(Blastomussa Wellsi), acan lords (Acanthastrea lordhowensis), any Micromussa will probably be considered rare and cost an arm and a leg, dunkan wiskers (Duncanopsammia axifuga) although I dont like em you might, various Enchino (Echinophyllia) and Chalice ( Echinopora) variations. whats rare and not will be determined by the coloration and location they're from.
there are many sought after zoanthid as well: Tubbs true blue, superman, gold rush ect ect ect.
expect to pay anywhere from $10-100 a polyp for any variation of zoanthid or LPS considered rare.
I would probably upgrade the lighting if I were you. Not that what you have wont sustain the above its just the fact that by the time you've bought a few of any of the above considered rare you have already paid for a T5 or MH set up and that will allow you to keep rare monti's and SPS which opens up a whole new door. So far the only thing rare I have is deep red and blue blasto with superman montipora on the way. Just those two alone cost close to $300 and are just in the 2.5" range (7 blasto polyps).
BTW as stated candy cane is one of the most common and cheapest of all LPS. no coloration is considered rare. dont be fooled because they are turning up aquacultured alot lately at ridiculous prices (for the price of a 1-2" candycane frag you can buy a whole colony of wild which do just as well)