Noah went into his big boys bed just before his 2nd birthday - it was one of his pressies I brought all of his linen too and gave it to his as a present too. Scab aren't I? LOL.
I plan on moving Tehya into a bed probably around the same age, although she is much smaller in size so she might stay in the cot longer... who knows. I am looking at the old fashioned daybeds for Tehya, as I plan on doing her room a shabby chic style. The lady at the bad shop told me to put it against the wall the opposite way so that way it still had a side up, IYKWIM. So thats a thought for us.

Oh yeah, I used the rail too.

Joel we moved around 2ish too, I had a waterbed at the time and whenever he woke and got into it he would sleep great so thats what we got him. The transition was great, no need for a rail there and he slept beautifully in it. Brandon was about 2 also.

The only thing I would worry about with removing the cot side preparing them for a bed is that most cots are higher than a bed, if they fall out it's a pretty big fall, well it is from my cot anyway.