I installed a 7200 Hitachi in my Penrym Macbook and its silent, cool with a very tiny vibration (you have to really feel for it, to feel it). Its perfect to be honest.
If you look at the bench marks, 7200 is nearly always faster (with exception if it nearly full and you are comparing it to a half empty, much bigger sized 5400rpm drive).
From real world tests, people tend to say they get noticeable differences when they install a 7200rpm drive on whatever tasks they find they are doing. I have so far (including web surfing and email, everything opens faster, documents are available faster). The reason is, it actually is a good upgrade, not just because people say so. Benchmarks blabla bla (have a look at barefeats.com) - But often real world tests are more important, because it is really about how you feel about it, because it is going to be you who is noticing it or not.
So the above post is wrong....