What startup programs are necessary?

msconfig>stratup is one thing but I'd be a little cautious what non MS services you uncheck under msconfig>services.
eg. uncheck "Macrium Reflect Image Mounting service" and you won't be able to mount Macrium images - at least my experience.

Wouldn't a user advanced enough to use mounting know that Service is needed to mount their images? Do you have another example?

One can always google the entries to see exactly what they are.

I find that some Startups hide in msconfig Services tab so they won't be turned off. I only want free riders of my choosing.

gregrocker said:

Wouldn't a user advanced enough to use mounting know that Service is needed to mount their images?

Not necessarily. One could assume the service would automatically start when called on.
Others may fall into this category and my point was to use caution.
I haven't got any other examples because I haven't bothered looking.

my startup programs had entries named "igfxtray" and "persistence", is it safe to delete?

igfxtray is an app from intel for their graphics cards. The app stays in the system tray so that you can change some settings. It is fine to not having that run. I'm not sure about the other one.