I agree with you both; it really depends on what you are doing/what apps are being used. I think it's important to look at the whole picture.

But too much emphasis is placed on HDtune/HDtach because it's easy and convenient to test. But if you had to look at 1 test that tells you the most information, it would be the complete battery of tests from IOMeter. It will tell you everything that that HDtune/HDtach will tell you and much, much more.

jcool - "workstation" pattern for IOMeter is defined as 8KB / 80%read / 80% random