What is safe to uncheck in autoruns to make pc start up quicker?

"I assume a fairly normal XP, Vista or W7 install (which is it?).

Look at the manufacturer column. To be safe, keep anything to do with Microsoft, Intel (or other processor type), or the machine manufacturer.

Ditch anything else that you know you don't need on startup. Common ones that get in there include itunes, quicktime, MS office, java updates, windows media player, any palm device or mobile phones that you connect to the computer. You don't need these on startup, although most of these are update checkers that you'll have to remember to run manually every few weeks. They may well put themselves back in the startup list after an update, so you'll need to remove them periodically.

Also, if it's a fresh OS installation, you may well have some trial software and other bloatware from the manufacturer which you can fully uninstall."