Should I buy a case?

I am buying a black iPhone this week and wanted to know if you guys would suggest buying a case alongwith it.

I have never used cases on my phones, as I don't like them. But, this is going to be my most expensive phone ever. And I am worried about scuffs and marks.

I am usually careful while handling phones - cheap or expensive - and usually don't drop them.

BTW- I am getting a discount on the unsubsidised purchase, so, would prefer to bundle the two together.