If he is not actually climbing out of the crib and you don't believe that he is ready for a big boy bed - try tethering the crib to the wall. If you do think that you son is ready for a big boy bed then go for it.
I personally don't believe in toddler beds - I felt that they are just another piece of furniture to buy, we went straight from the crib to a single bed for my son when he was 2 years old (mind you though that his single bed does not have a box spring under it, it just has a bunkie board so the bed is as low as a toddler bed would be)- we let him help us put it together so that he felt like it was really his. Instead of putting a gate across his doorway - we put it on the steps, shut the bathroom door put a childproof nob on it and kept our bedroom door open, just in case he needed us. Although, until he was potty trained he had a rule that he wasn't allowed out of his room unless we came and got him.
enjoy your little one,
Mel