SIL Unicode fonts Scheherazade works really good
Arabic fonts for Mac
Accordance Font new Unicode font
The Brill Unicode font but beware of usage restrictions Great resource for comparing the best lexicons at the same time syncing pages by root

Lane's Lexicon online (Tyndale House)
Lane's Lexicon online with color coded entries; still in development (Quranic-Research)
ArabBible - Arabic Bible software for Windows, Mac. Includes translation, grammatical analysis, and other features.