Might sound like a stupid question but what kind of condoms do providers perfer. I like to have some incase...

Especially if the normal size don't fit you well.

So, get what you prefer, as long as it is a latex or urethane type (No Lambskins!), and bring it in a sealed box.

The range of preference among providers as to specific types is quite large, from what I've seen.

Lubricated or un lubricated?  

I don't think that matters.  Of all the things that providers may or may not have on hand the one thing I've never seen them be without is plenty of lubricant.