I wouldn't but that is just my opinion. I think you can put two different metals in your kitchen but don't use identical pulls. Use pulls that are complimentary to one another but in the different metals. Think of it as wearing two necklaces - one in silver and one in gold - you wouldn't wear the exact same necklaces but rather ones that are complementary- different lengths, different pattern.

You could do pulls and knobs, or ORB and glass.

What are your appliancss and light fixtures? Three metals might, depending on the rest of your kitchen details, start to get a little much.

My dishwasher and fridge will both be panelled in the white oak so the only metal seen will be the stainless steel of the hood fan (it is one of the glass and stainless models), brushed metal of the faucets and the stainless of the gaggenau ovens (stainless covered in glass). The sinks are silgranite in biscotti colour. Attached is a picture of four of the handles I've been looking at, they all come in both finishes. The top two are the same, different sizes, different finishes. I take your point about necklaces, but as I tend to like things rather plain and simple, I worry that different styles mixed around would look busy. (I would seldom wear a silver and gold necklace at the same time!) I also worry that two different colours would look busy, I just like the dark with the teak.

http://i1056.photobucket.com/albums/t368/carolmack/P1010945.jpg