The way the storylines are being written today, it almost seem the writers want to keep some suspense going. Remember the last time Taylor and Ridge were supposed to get married, there were all types of rumors spewing. I recall reading a spoiler to indicate, that Taylor and Ridge do get married and it didn't occur, so I don't think this one is going to be as simple as it looks. There was also a rumor that the Logan sisters take Steffy hostage and someone gets hurt, not forgetting the tittle-tattle that Hope gets stuck in a cable car and can't stop the wedding. So who knows?
My personal speculation (unconfirmed report) tells me it will be Hope and Liam, although I would rather it didn't happen, but no doubt, it would certainly create a spectacle! Cinderella story!