I suspect you're doing this to help speed up your boot up time. First, before doing anything with msconfig, go to the "Programs-->Startup" menu folder and see what you've got in there. It's best to just delete those shortcuts rather than fiddling with their respective msconfig settings.
Otherwise, I suggest checking out a tutorial on
disabling msconfig startup programs in Vista. You want to check out what you've got listed in "Startup" as well as "Services".
As for what services to disable, initially I'd disable what is obvious. For example, Apple installs some services if you use iTunes and have an iPod. But if you don't use it much, it's best to disable those services. You have speakers on your computer, so I'd leave the IDT PC Audio alone. As for the Intel Common User Interfaces, I don't see any of those listed on my system, but perhaps your hardware setup is different.
The best thing to do before un-checking anything you're not familiar with is to search for it on-line. Usually you'll find a website that will tell you information about the program and if it's really needed. Some software has services loaded at start-up time to make them load up faster when launched, or automatically when something happens (like plugging in an iPod). Often you get by without that, as the time saved is marginal and thus only effective if the program is used frequently.
One last thing. While msconfig is a useful interface, a more powerful one is "services.msc". In there, you can more thoroughly control how services start (automatic, manual, disabled, etc). If there are some services you know that you definitely don't need immediately after boot-up, you can set them to "Delayed Start". This can help make your desktop available for use a little quicker upon boot up.
