Gandi is very good, spiritual and philosophical is awesome. He is probably the best.
The Chinese leaders are also very good with the Pavilion, and Qin Shi Huang has good characteristics for it (industrious, protective). Ramses is also very good.
Saladin may not be the best at it, but his traits make a culture victory a solid option and he may less suitable for other forms of victory, so when I get him on the start, I usually think about a culture vistory.
Good characteristics are --
Spiritual. May help you found a religion, cheaper temples is really important, and switching civics when you get attacked is great.
Philisophical -- Great artists, great artists!
Industrious -- You want the culture wonders, both for the direct culture and especially since they produce great artists.
Many people feel that Protective is a weak trait, which is probably correct. It is probably more useful for a cultural victory than other forms.
Bad traits are probably Aggressive, Expansive, and Financial, which are all better for other game forms.
Oddly, creative isn't a great feature, the 2 points/turn doesn't add up to a lot of culture, it is really mroe useful for fast expansion. Charismatic is just a good trait, its good for culture but it may be better for traditional games. Not sure about organized and imperialistic also seems better suited for other games.
There are a lot of threads out there on this topic, you may want to search.
Best wishes,
Breunor