Sometimes as techies, we want to keep programs from running at startup. This helps get rid of spyware that is running in memory. Once stopped, we can eliminate malware with Spybot, for instance, without running Spybot again on reboot, which is time-consuming. Also techies often are asked by clients to speed up old computers or new computers running Vista (lol!!), and stopping unwanted programs from running at startup is a good way of doing this. Using msconfig is another way, but problematic since it turns off System Restore, which is another useful tool to return to a computer to more pristine state without reformatting.
Here is a site that tells you how to stop startups by editting the registry. I have found it extremely helpful. However, only edit the registry if you make a backup first, since editing it incorrectly can cause major damage or problems.