Well, I am a metallurgist (okay, okay, I studied metallurgy at UCLA and worked as a metallurgist on-and-off for 8 years - I've been a computer programmer for the last 16 years- I don't want people to say I change my claimed area of expertise to suit the thread). From a metallurgical standpoint, there's nothing that makes any of the available finishes uniquely "interesting". The finishes with proprietary sounding names are all variations on finishes that have existed since the beginning of time (in other words, since I was in school - When we still had textbooks and graph paper.). They are nice and slippery, and not susceptible to galling, so they are good choices over stainless. The only real purpose they serve is to keep a poorly maintained gun sliding along a little longer.
If your gun is an SA, I'd say talk to the SA Custom Shop. If your gun is a Glock, nothing is going to make it look like anything but a Glock. There's a Glock with $2000 in custom work on it at my LGS, for $1100... Nobody is going to buy it. It's a Walmart Cinderella.
From a shooting standpoint, dead flat black park or paint is best. Not very interesting from an aesthetic standpoint.
If you're fussy about the finish of your gun, choose something that's easy to touch up, like Krylon camo paint. I'm considering Krylon over Park for a fun finish on my Citadel.