Good Lord. The first 10+ threads are run by Sony trolls and fanboys. What the heck?
To answer your actual question:
The DVD drive runs loudly because it's faster than the Playstation 3 by a decent double-digit percentage. Because it's faster, it runs louder. Its not actually Microsoft, MrPickes, it's the various makers of the X360 DVD drives (Hitatchi, BenQ, Samsung, ect). They've made them quieter with each succuessive generation of X360 DVD Drives, but are still sometimes louder than PS3s, depending on models.
As for the power source - unlike the Playstation 3, where it's almost entirely (or entirely) internal, Microsoft favored the brick being on the outside. Ever notice the fact the PS3 is a bit larger than the Xbox 360 console? One reason is because Microsoft would prefer an external power supply, and shrink it as the CPU/GPU size gets smaller, and better.
And remember, for the 3-4 Sony trolls and fanboys in this post: This is a Microsoft forum. Tone down your anti-X360 banter (which was entirely wrong from each poster), or your getting banned. This thread will be locked in short order if the BS keeps flowing from your mouth(s), Failureisnotanoption. Posting random fanboy banter without any specific claims to back it up rather than "OMGH, The PS3Z IZ BETTERZ" will result in a ban.
Back from the dead, I'm afraid.