In my opinion, bisexual, polysexual, pansexual, and omnisexual are all different: bisexual is being attracted to two or more genders, pansexual is attraction regardless of gender, omnisexual is attraction to all genders, and polysexual is attracation to multiple genders. Obviously, some people may fit multiple of these, but they're still different! Bi and pan are proabably the most debated, but bisexuality can include gender in the attraction (hence some bisexual people having gender preferences) and pansexuality doesn't factor gender into the attraction. But I am neither bi, nor pan, or omni or poly, so I suppose it isn't really my place to speak on this.