Will SATA 7200 drives run faster on latter motherboards?

Will today's crop of SATA 150 hard drives (excluding Raptors) run faster on the next generation of motherboards due out in a year or two with faster SATA controllers on?

Im not 100% on this but as far as i know the main bottleneck in hard disks is the rotation speed not the interface. I heard that SATA is only faster because teh transfer rate is more stable (i think) so sustained speed is better, but I dont think that any SATA drives at the moment (especially not 7200rpm ones) are getting anywhere close to 150mb/s, so I doubt that a 300mb/s interface will make them any faster unless the drives are super fast spinning like raptors or a 15k SCSI drive but an SATA version.
Dont quote me though i might be wrong about that.

I don't think so, it's the drives that are too slow, not the interface. I'm sure you've seen info about ATA100/133 being theoretical and that no drive ever really can reach these speeds except in small quick bursts, same with SATA. Until rotational and seek times speed up, it's all unused technology.