The purpose of benchmarks is basically to show, potentially, the fastest product in the category, but primarily it is more important in showing what you don't need. I.e. you don't need to pay for a C2D to do the things you love to do, you can save some money and buy an AMD X2.
Now if I owned a older system, thereby I mean a non-64 bit apparatus, then upgrading to a phenom will be just dandy, same or better speed plus four cores to boot. How can you loose?
Nice if we left the benchmarks on the site they were posted rather than drag them into the forum, but since they're here you will notice that way way cheaper cpu's than the latest Intel offerings can do just a fine job.
30 minutes more for a phenom to encode a DVD, well I'm sure the movie industry will love you for it. If I am going to take the trouble on such a large project as this I want quality in the end product and a stable machine to do it. Speed is only a distant secondary objective.
Components are warranted to run at a designated speed and the rest is pot luck. If you can get a C2D rated at 1.8GHz to run at 3.2, that's great, but don't expect it to keep doing it as that stress is continual and adds not only heat to the cpu, but heat stresses the rest of the system as well. Add to this the extra cost, risk, power consumption and extra cooling requirements, and very quickly OCing becomes a very poor investment in time and money for very little if any long term gain. Short term bragging rights only. Does the machine run stable at that speed continually? For example in Canada with sub-zero temps in winter is a lot different environment than an Australian summer of sustained 100 F.
My opinion is this, if you have a new rig and need to OC at time of purchase you have simply under invested for your needs. If you have the desire, the insatiable need to explore the limits of your parts, do it by all means, post it and impress us, but don't bag out the other guy, because he/she has found merit in a different formula. Remember it's because there are so many different roads to go down that make this industry such an interesting one.