I'm not sure that "How could ANGELA go from JORDAN CATALANO to COREY HELFRIK" is actually a question that requires a poll... but it is an interesting question none-the-less.
I don't think that Angela really selected Corey as her next crush. Remember that she had a dream about him, a dream a Corey Helfrick and towels made out of crackers
Angela had not gone to bed thinking she was over Jordan, or that she needed to get over him by finding someone else, she simply went to sleep and had a somewhat sexual dream about somebody other than Jordan Catalano! Hence the surprise and overall joy that morning when she wakes up. (Dreaming about Corey sexually while she sleeps, most likely has very little to do with how she actually feels about him.) (I'm starting to think that I've maybe talked about this on another thread...)
It is very true that there are obvious differences between Corey and Jordan, but this switch is easier to believe when we remember that Angela didn't really choose him, and that actually she has to convince herself that she has any interest in him at all:
I like him. I do. And I want to pay this much attention to every word he says.
It isn't until she knows that Jordan is watching that it occurs to her to use Corey to try to make Jordan jealous (btw: I love that look he gives her as he passes by them, something like, "Whatever, this is bull shi--").
The second time, when Angela comes onto Corey, it is a direct reaction to feeling that Jordan and Rayanne are laughing at her for being "some innocent little twit who they can treat as bad as they want," and she uses Corey b/c he is conveinant. He is convenient in that: there were no emotional hang ups with him (as there would be if she had chosen Brian); Jordan knows little about her "relaationship" with Corey, so it would be easier to believe something about them (although by that point, I think what happened back stage had very little with Jordan, or Rayanne for that matter) finding out about it); she had already flirted wit him slightly, and knew she would be painting the oak tree with him etc.; she does not find him threatening or intimidating; etc... Angela's interactions with Corey in "Betrayal" ahd very little, or nothing, to do with any genuine feelings for him, and was not something, I feel, that she was going to pursue much further than that day. ((There could be some debate on that point -- if Corey had welcomed kissing Angela, how long would that have gone on for? That day? A couple of days? Weeks? What was she willing to get herself into?))
I really don't think that Corey is gay.