It is probably cedar. They used to have kits for walls and the boards were always installed on an angle. If you could get a cedar board and replicate what has been done, this would let you play a bit with paints.

My first thought is an exterior wood paint/stain which comes in many colors. This is a heavier paint, not like furniture stain, but lets the wood show through. Not sure it would work over the current wash. The HW stores usually have a paint board showing the different options.

With the cedar boards, I think that any paint would allow the wall to retain the look of a wood panel. It has enough texture to do this.

Also the fireplace, it needs paint too. I wouldn't normally suggest this, but one of our posters painted her whole wall and fireplace black. It was beautiful and well worth seeing. In a basement and didn't have the windows you do. Maybe someone can remember the poster. I ran a search and spent way too much time on nothing coming up.

If you want to try to return it to the look of wood, you might want to try using a gel stain on it as it will give you more of a feeling of graining than will paint. But you really need to play with it with practice boards first as, depending on how rough the boards are, it can look great or awful.

Instructions on dry brushing after white washing below. Looks like the way to go.

Here is a link that might be useful: white washiung vs dry brushing

cat_mom did her basement...all black brick..stunning.

Here is a link that might be useful: cat_mom's fireplace

Ooh that is quite amazing.

Cedar, huh? Hmm..that could be. It is quite rough under the paint.

Some things to think about. We'd actually like to take some/all of that brick out. We will not be using the fireplace, until we can afford a gas insert.

Thanks for some ideas!