For me, I like dark bamboo/wood chopsticks. I usually get the ones with the square shaped handle part since I'm in China, but square/round really doesn't make a difference. Lacquered, ivory, bone, metal, etc... can be slippery, but chopstick technique can influence that slipperiness as much/more than finish.
I just got a few sets of antique jade chopsticks that I've used and are kind of cool, but the weathering made some kind of slippery for noodles and stuff and I am always kind of afraid of someone dropping them, especially as the meal goes on and we drink more. They are cool and a conversation starter, but they were definitely an impulse purchase, and if I never would have made it, I wouldn't really miss them now. As for those Korean metal ones, I've had like 8-10 pairs for about 5 years now and all but the cocktail stirrers collect dust in a drawer because they are a pain in the ass to use.
I would recommend a standard bamboo/wood/whatever and then if you want something more interesting look in to different chopstick rests or other accessories.