I recently went through this carpet->wood on stairs conversion myself. We had 17 stairs + a landing and an extra step up to the landing. I used pre-finished 5" maple planks (engineered) on the treads to match the wood in the rest of the house. We bought pre-finished nosing for each step ($$$). For the risers I used 1/2" birch plywood painted white (nice contrast with the dark wood). Overall, I'm happy with the end result. However, it wasn't easy and took a long time. 1) it's a lot of work, and, if you don't put some thought and time into it, it will show 2) Walls and stairs are rarely straight, perpendicular, parallel, or aligned in any direction to make this job easier. Each and every cut will be unique 3) Our staircase has a stringer on each side - no balusters to worry about, but that doubles the number of unique cuts to make 4) pre-finished nosing is expensive. Our steps are 42" wide. The nosing comes in 78" sticks. I didn't want a splice in the nosing, so that meant one stick for every stair 5) After we started, I found some places online that sell one piece treads. I'm not sure that it would have been cheaper than fitting multiple planks on each step, but it would probably be a lot less cutting. 6) with 17 steps, the less trips down to the saw and up to test the fit on the top step the better. Of course the top stairs are probably going to be the ones hardest to get right I found the hardwoodflooringtalk website to be very useful during our entire install. There are several guides and a busy message forum. I recommend you (or DH) spend some time browsing it before starting. Unfortunately THS won't let me post a link to them here, but a google search for "hardwood flooring talk" should get you there. Good luck!

Courtesy of another GW'er, I've found another source for hardwood stair treads at a much more reasonable price. Orubuis--I don't remember the specific product that I used on my stairs but it was some kind of penetrating tung oil. Wasn't Waterlox because I haven't used Waterlox yet. But Waterlox can go over stained wood--that much I know. Just be sure it's an oil-based stain. Another factor with wooden stairs is the noise issue. For that reason you may want a runner. My stairs are back stairs & get tons of abuse. So, yes, they have scratches. But the finish isn't worn thru, chipped, peeling, etc., all the things that can happen to film forming finishes like varnish, poly, etc. And they're easy to sweep down and clean with just a swipe of a rag vs hauling out a vacuum and living with the plain nastiness of carpet, esp. with the location & use of my back stairs. Here is a link that might be useful: Hardwood Lumber (stair treads)

Safety first and to heck with trends. Personal story: On July 1 I tripped on the concrete stairs of the out-of-state motel where we were staying and broke my leg. The bone itself has healed decently, cast is off, but am in my sixties (no osteoporosis) and am in a wheelchair now due to severe pain in my leg and back when I walk (which I do try to do, for exercise). Looks like the chair will be in my life for quite awhile. Meanwhile, my orthopedist has forbidden me to use stairs at all for the next several months (we have eight stairs going up to our front door!). I will never look at stairs the same way. I would put the safest material on the stairs; if that would be a certain type of carpet or runner, then go with that. Please don't write to wish me well, absolutely not looking for sympathy here, am fine, and Do Not Want To Hijack This Thread! I just want to emphasize the places in the home where safety must come first!

@Pam P. Above are couple of stair jobs we have done before. Hope they can help to visualize your project a little better. The first used the floor boards and stair noses to build the treads with full white risers. The second used the full treads and white risers. I like the second more than the first, but cost you more too. White riser is where you can save money and still look gorgeous IMO. As K Laurence and Cinar suggested, try to find a specialty wood floor store or hardwood floor contractor in your area with good reputation. They can take you to the right path and deliver a happy result. Good luck with your project!