Hi Leah. As you like timber what about using a decorative timber screen to fit that space? Enough decoration to give privacy, but open enough so light can come through. Kind of like a picture that draws your eye rather than an ugly square of glass. I'm sure houzz has an article showing these decorative screens in various styles. I have some typical geometrical chinese wooden windows in mind, but I'm sure you could find some laser cut specialist to do your design in metal, or a carpenter to do it in wood.

I like glass: it makes the room look modern and spacious and bright. But I can certainly understand your worries about keeping it spotless. (Glass only looks nice if it's clean.) If you are worried about "too many lines" would changing the changing the colour of the iron to something more subtle be an option for you? I agree with Matthews about keeping the balustrade simple and leave out the ornament. The other thought I had was that your staircase has open steps. I find it more constistant to keep the railing open as well instead of closing it up on one side.

Aluminium unless you like maintenance and painting. Check out AWS windows- they have thick-framed aluminium windows- it looks like timber ;-)

Maybe you could consider a bar fridge that may fit where shelving for microwave is... this could hold your daily used foods and then have your larger fridge in a garage area to hold things less used? http://www.google.com.au/shopping/product/879529927670433319?lsf=seller:9455133,store:5516113429362448143&prds=oid:5429649432223856483&q=bar+fridge&hl=en-au&ei=67UVWMGnIYKR8wWl0ZHQBA&lsft=gclid:CMHmgr2UgtACFdWWvQodHk4MvQ