<p>Does anyone know how many options a drop down list can have? Is it unlimited?  How many before performance degrades?</p>

Does anyone know how many options a drop down list can have? Is it unlimited?
I imagine it is unlimited in theory, obviously not in practice as a computer's RAM and the specific browser's limitations come into play.
How many before performance degrades?
Again, this would depend on a few factors, at the least the specific browser, the computer's memory and processing power.
EDIT: From experience, I have had drop down lists with thousands of options. It wasn't ideal though because who wants to scroll through all of those? This is why an auto-complete of some type is more desirable for numerous reasons, especially the end user's experience.