Serious video editors pay attention to sound as well, in post production. The problem is often finding the right sound online or elsewhere. I just discovered that the pc strategy game entitled Civilization 4 (2K Games) installs a treasure throve of wav files on your pc that Vegas instantly recognizes. As the game covers pretty much all of civilization, the wav files are extremely diverse: the probably unuseful dying horse and various dying soldiers, the usable foot in mud (8 varieties), foot in snow (8 varieties), cows mooing (7 varieties), ambient sounds for hospitals, airports, hindu temples...
The list is extremely long and very varied.
(The game costs $5 and is actually a very positively reviewed game in itself.) The game runs on XP and Vista.
http://www.vimeo.com/2452342