It has been a long time since I crossed the border but I have been told that you need a birth certificate as well as other I.D. to cross through.
Something you may want to check before going. I mean it would suck to get that far and not beable to cross. Just a friendly reminder.

Sorry if this has already been mentioned in another post

I was just accross last week its Birth Certificate/Drivers License (Or other Photo ID) or a Passport (Much Better)

Drivers Licence is all I've ever needed. Thats in Buffalo anyway, but it should be the same all over. If you had your BC with you it would be a wise choice.
Good Luck

For those of you bringing cars down, have you been hassled coming back up?

I would think that customs might take a dim look on bringing hundreds of dollars worth of tools across.

Any comments?

^^^
If you're worried about that, you can do some paperwork on your way out of Canada to register your belongings.

But generally, they don't hassle.
I've even told them I've picked something up and they just said "have a nice day".

Take your Birth Certificate. My friend was there last week and he said he needed it. Or a passport. Other than that you should get some insurance, health that is. You can get it at the bank or travel agency I believe. Its very cheap, and worth it if something happens. Without it the americans might not even look at you. Also, yes, claiming your items before you go in is the best idea. To avoid problems when comming home.