How many ways can you turn an image black and white in photoshop?

I love black and white images and often turn my images to mono to see what they look like. I recently watched a tutorial on how to do this in Photoshop CS using Hue/Saturation. I have never ever used this system, so it got me thinking. How many ways are there in photoshop to turn and image black and white and which way gives the best results? Here are the ones I know of and examples of what they look like.
Lets start with the obvious ones. I have used this image of Selby North Yorkshire as the subject image

I chose this image as it has good highlight and shadow definition as well as strong colours. Ok here we go!
1. Greyscale: very easy to do go to Image-mode-greyscale discard colour info.

I do not recommend using Greyscale as the resulting image is often bland and flat. You also have NO control over the final image. You can use levels or curves to lighten or darken the highlights, shadows and midtones. but individual colour channels are unavailable. For those unfamiliar with channels look at the colours in the original image. There are reds on the building, blue in the sky and greens in the grass. they remain when an image is turned B+W and can be individually altered when using certain methods of conversion. All will be revealed!

2. Desaturate. Again easy to do: Image-adjustments-desaturate.

Not that much different to greyscale again you have no control over the final image, like greyscale only levels and curves for adjustments. No individual channels.

3. Gradient map. Image- adjustments-gradient map. click on drop down and select b+w box see arrow.

As you can see the resulting image has more contrast and darker shadows.

Again no individual channel control.

4. Channel Mixer Image-adjusments-channel mixer

Notice that the monochrome box must be checked. This turns the image B+W then you can alter the 4 sliders to get the desired effect. For this demonstration I used Red+200 Green +100 and Blue -200. Please notice that the total must always read 100% I lowered the constant slider to slighly darken the image. This is a pretty good way of turning an image into mono as you have control over the RGB channels.

I think you will agree it's a much better result.

5. Hue/Saturation Image-adjustments-Hue/Saturation

Notice on the box that opens I have adjusted the saturation slider to -100, this turns the image mono. then click on the drop box and you will see 6 coloured channels. You can now click on these individual colours and alter them separately by either raising or lowering the lightness slider to get the desired effect. Lowering the Cyan and Blue channel usually makes the sky more dramatic.

6. Black and White. Image-adjustments-black and white. I use this tool solely for my mono conversions. I use CS4 and I am not entirely sure when this powerful tool was introduced maybe someone can tell me.
This mono conversion gives ultimate control

In the presets there are automated selections in the drop down menu that you can choose to try they are well worth a look, however for total freedom you can custom choose each cannel and alter the sliders individually to get the desired effect. You can see the setting I chose and view the result below.

If you have the black and white tool use it for your conversions it is the best choice in my opinion. If not Channel mixer and then Hue/saturation are the next best two. The others are really a last option and not ones that I would use unless there were no alternatives. If you know of other ways of mono conversions let me know.