I highly recommend dog and cat hair. ;)

Our's are carpetted. Vacuuming them is the pits. If I had to money to do it, I'd have them carpetted in an oriental style rug with the pretty brass bars to hold the carpet in place.

I love tile risers with wood stairs. Have you checked out the stairs pics in the Gallery? There are tons of pretty ideas there.

We have hardwood stairs, but they were so slippery we actually put down safety grip tape to prevent people from falling (our stairs are a whopping 8' wide so carpet runners won't fit).

I have paint on my stairs - a special deck paint that is completely non-slippery.

I love it because I can change the color of the whole staircase with very little effort - and I do change my mind quite often!

Oh, I can answer this:

My daughter's clothes and books!

:)

Seriously, you could consider hardwood but with carpet runners if you want quiet. Or tiling the risers, as sarschlos recommended; that's one of my eventual plans when we take the yucky carpet off the stairs and redo them with hardwood to match the floor. My "plan" is to redo the risers with tile in the same material as what I'll be recoating the fireplace with. You know, for a weekend project LOL...

Or paint is also good, a la Daisy--the color of your trim is one obvious choice.

White paint and the very popular dog fur. 5 years ago it was supposed to be a temporary fix from the carpet and dog fur LOL.

I am going to strip the treads and stain them to match the laminate on the first floor, keeping the risers white. Soon. Really, I mean it.

The stairs are the original oak and my DH refinished them about 5 years ago and we had a runner of beige karastan berber carpet installed down the middle- so the edges of the wood show. Nice and quiet with the 8 paws pounding down the steps, and the color blends in with the requisite dog hair here too.
One day I would love to have the oriental runner with the brass bars.We almost bought them when we bought our room sized orientals for the rest of the first floor. Now I wish we did.