I really like
Thalia, however I probably wouldn't use it, since we have a book store over here that carries this name.
I pronounce it tah-LEE-ah.
I'm not a fan of nicknames, but
Lia probably makes the most sense.
I like
Thaleia, too, but I'm sure people would misspell her.
Pairing suggestions:
Thalia AglaiaThalia AstraiaThalia DanaeThalia DioneThalia EudoraThalia GaiaThalia HemeraThalia HestiaThalia IoneThalia Melia