I have three boys, one of whom is almost 2.5 now. He's giving us a lot of trouble (much more than his older brother did) right now. Although he started talking early and has an excellent vocabulary, he escalates everything to a scream right away. Either it's a scream with no words or "I need a KLEENEX!" or "I need more MILK!" at the top of his lungs, as though we've been neglecting his requests for hours. It's completely exasperating. Minor disturbances often provoke roll-around-on-the-floor tantrums.
Although we haven't figured out how to stop this behavior, we are definitely getting through to him in small ways. When he screams or asks without saying please, we tell him to use his words and to ask without screaming or whining, and we do not get him his milk, Kleenex, or what have you until he asks more politely. Now it's enough for us to say "Try again" when he screams for something, and he asks more appropriately. This took A LOT of repetition, but it's finally working. The key is to never do what he wants until he stops screaming about it.
As for napping, we also transitioned our son to a toddler bed not so long ago. However, we didn't get rid of the crib. I don't know whether that's an option for you, but for us it has been great. I tell my son that if he gets out of his bed, he will go in his crib, and I do it -- the FIRST time I hear him get out of bed. If he stays in his bed (even if he has toys in bed), he takes a nap. If he gets out of bed and plays, he usually doesn't nap. If he is having a hard time settling down, then putting him in his crib with no toys gets him to sleep within 10 minutes. Most days, though, he sleeps in his bed. I even hear him repeating to himself, "If I get out of bed, I will go in crib."
Our son also has started fighting bedtime. One thing we've started doing recently is introducing some fun games to disguise bedtime routines. I found these suggestions in a magazine. We hide the toothbrush, dental floss, toothpaste, and pajamas in a particular room and have our sons look for them in a scavenger hunt. As soon as they find an item, they have to use it or put it on. If your son uses a pacifier or has a favorite stuffed animal he takes to bed, hide that too. Then, once the scavenger hunt is over and everyone is ready for bed, we take a quick walk. If it's dark, we bring flashlights. By the time we get home, the boys have had enforced calming time sitting in a stroller, and they go to bed without complaint.