It's like negotiating with, well, a two-and-a-half-year-old

Potty training. It has been one of our biggest hurdles as of late, and I am not sure how to handle it. Originally I was not in any sort of rush; I wanted CR to be completely ready for the transition from using diapers and Pull-ups, to removing the "middleman" of sorts and going directly to the source to do his business. Before the holidays, we really had the peeing thing under control. He rarely had accidents, even when wearing underwear to the park - he would signal the need to go, and we would make it home in time to avoid having to change his entire outfit. Once we went home to see the family for Christmas, he seemed to go back to the drawing board. The whole pooping thing has never been on par with what is socially acceptable...I wanted to get over the liquid hurdle before I attempted to deal with solids. But at least at one point we had one battle won...had is the operative word. It's not so much the accidents that occur, but it is the utter refusal on his behalf to even attempt to go anymore. It's like I am asking him to lite himself on fire.
So today, I decided that I would try to reason with him. He is getting to the age where he can partially grasp a concept if it is broken down for him. I told him that instead of screaming "No!" when I asked him to go to the potty, that he think about what if I always said no to him...like when he asks for things he wants (marshmallows, a squeeze yogurt, to wear his PJs after the morning passes by, for a new Cars character...you get the point) - on average, if he has already had a decent meal, or if he asks politely, I often say yes. He did not like my idea...he does not like the word no when it pertains to him (why would he?)
After sitting on our bathroom floor, "reasoning" with him and conceptualizing with him, he stood up, pulled down his pants, and asked to be put on the toilet. I swear a chorus of Hallelujah, Hallelujah rang down from above. With a quick flush, we pulled his undies back up, and he was off...five minutes later, he in turn, pooped in his pants...one point for Mommy, quickly switched over to one point for poop-boy. We will get this...right?

(image from here)