An awesome looking keychain yo-yo (actually designed as to fit as a phone hanger) is the yoyo monster 3Points
. Can't link to it but it's easy to find with a simple Google search. No idea how it plays and kinda pricey too.
I agree. the Immortal Star(goes by a few other names too) is really cool looking. But, you should watch the YoYoSkills review of this. I was going to get one for the "it's cool looking" factor, but based on his review, I opted not to because it's a heavy beast, at around 80 grams. Too much even for me.
Unfortunately Chris didn't review it with the plastic stacks (apparently they were missing from his package). The metal stacks are cool but way too heavy, no stacks and it plays too light, but the plastic stacks give it a nice weight. For the price and it's definitely worth checking out for those interested in fun novelty yo-yos.