A, A, A, A, and A:
One (Former Cube-dweller; Current Expert on Messy Eating): It sounds like you've already made a noble effort to send hints. But this is a guy we're talking about, right? If he's anything like my guy, you need to spell it out for him in language that is so completely unambiguous it will probably feel rude (e.g. "When you eat, you sound like a warthog in heat. It's so distracting I can't work."). Such candor can be awkward. But you have access to an amazing resource that Mr. One and I don't: the H.R. Professional. Yes. I am advising you to be a snitch. But it's in the interest of the greater good. Your message will be delivered with tact and discretion, while preserving cordial relations with your cubemate. And your friendly H.R. peep is trained to handle this sort of thing -- technically, harassment "occurs when an employer creates, condones or permits a hostile, intimidating or offensive work environment." Clearly this qualifies.
Two (Professional Noise-maker and Perspective-giver): To she who's ears are being violated: use a headset for your phone and when not on the phone, use them to listen to your Ipod.
Three (Resident Female Frat-Boy Poet):To the chagrin of my loved-ones and kin,
though I look like a lady, I'm a frat-boy within.
And so I would say (or perhaps I would shout)
"Dude, that noise is disgusting, please cut it out!"
Four (Easily Irritated): I knew a girl who had a similar problem. You can listen to her story and find my answer here: (skip to 1:45 and insert your beloved cubicle mate's name wherever she says "Ernie").
Five (Occasional Slurper, But Ne're Smacker): Just take his food when he offers it. All of it. No more smacking, and you've got a well stocked cubicle. Problem solved.