J.,
I just entered my own son, 20 months, into a toddler bed about a month ago. We put him to bed at the same time every night, with a routine to help let him know that it is "night-night" time (brushing his teeth, changing into jammies, etc.) Unless he's absolutely exhasted, he won't lay dow right away, but we have his bedroom gated off so that we don't have to have the door closed, but he can't get out. He will usually cry for about 10 min, then he crawls into the bed, pulls up his blanket, and he's out for the night.
Also, his bedroom is for sleeping and stories only. Only his soft toys are in there, and there's nothing plugged in any outlets, so we feel better about him being in there all night. Once the new baby is born, her crib will be put in there, as well, and the rule will be the same, that room is for sleeping.
Sometimes, you just have to stand your ground and give a little tough love. You are the mom, after all. Reasoning doesn't usually work on toddlers, so you have to be confident in your decisions and not faulter. And just know that him crying himself to sleep is not going to hurt him. I still feel a guilty twing every now and then when Robby does, but ultimately, I know he's ok, and that he'll greet me with a smile in the morning.