What bike do I get?

I am looking to get a dirt bike(my first one). I have ridden four wheelers for years but want something more challenging. I know I want a CR, KX, YZ, or RM. 125 or 250 and nothing older than a 2000. I remember reading somewhere that 125 are actually harder to ride because you have to use the clutch more to control the power. I have also read that the new (97 and newer) CR frames are not great for beginners. I am mainly going to use this as a trail bike with a few trips to the local track. I don't see myself hitting triples or anything like that so I don't need the best track bike. Any advise would be great.