If it makes you feel any better, I've got a Barracuda 7200.7, and I think it's pretty fast, it's certainly as fast as you'll get at that kind of noise level. Maybe try to concentrate on how nice it is to have a quiet drive!
I suppose the real issue is that hard drives don't get that
much faster from one generation to the next. But is your 7200.7 really too slow? Don't worry about benchmarks, I bet it doesn't take very long for your applications to boot up!
I use my 7200.7 for running multi-track audio, which is generally held to be fairly demanding disk-wise, and I've never had a problem with the speed of the drive.
As various other people have pointed out, the SATA-150 protocol simply increases the maximum theoretical bandwidth, which even at ATA 100 leaves plenty of headroom compared to the maximum rate a drive can stream data.
But you have
got a fast drive! And the super-thin SATA cable isn't impairing the airflow in your case!