I envy your wall space, I wish we had more! What has worked really well for us is using empty walls as our "brag" board. Do you have particular interests you love talking about? Putting something up about your family, a favourite subject, pet or holiday could be a great talking point. Our visitors get drawn to our fishing photos, where we caught the fish (Botswana/Amazon) and the type (Tiger fish/Peacock Bass). Although the photo print (size A0) could be printed really cheaply (~$50) at somewhere like Officeworks, I discovered that the frames (~$440 each) were the biggest expense. However, as we know we only needed to print a new A0 sized photo in the future, spending money on good, customised frames is worthwhile. We have also now tried printing our favourite shots on stretched canvas (~$100). The product gets delivered, usually in a week, ready for hanging much quicker than ordering a custom made frame ;) Smaller canvases range from twenty dollars to about a hundred. I found this company very reliable in terms of quality of print and speed of service: http://canvasfactory.refr.cc/HDLHZPH We have displaced our canvas photos from the wall and occasionally display them underneath the kitchen bench as you can see here (desperately covering up white space)!

I would look at a grey if the wall tiles are white. We used a colour called Limed White and it's fabulous, a real stone-grey with a hint of warmth in the hue.

Although I am a fan of grey and white, the grey tile doesn't appeal to me and I prefer the white floor tile but don't think it would work with your white wall tile as they appear to be 2 different whites from the photo. So if you like the grey, go with it or look for different options.

Or the reverse, long thin pots on top of the wall with plants that hang down. Maybe string of pearls plant. Imagine the wall will get pretty hot so that may be an issue. You would probably want to use a screening panel behind too. If you use a slatted one the pots could be affixed to that, otw you might not have room for a panel and a pot ...?