I have miles of decking at two houses. All timber when put in the Australian sun will suffer. When building our beach house we decided to go for Spotted Gum and let it grey. Why fight it? We applied Cutek, and will on a regular basis. At our main house we have lots of Merabu or Quilla. Will not grey the same, and leaches lots of red stain. Cheap, but would not use again. What ever you use, use a good quality oil that seeps deep into the wood not a traditional stain/or top finishing product.

The pic is taken so there's only a peek at the artwork- but if I was in that room it is that huge modern striking print that catches all attention, no doubt. And not in a good way.

I really like the pic that LesleyH posted. The wooden rail will be 'warmer' to the touch too, show less dirt and tie is with the stairs beautifully.....I thin it will 'ground' the whole look because, if I remember rightly, the stairs and front door are the only wooden features and the rest is a lot of very modern light grey/white/shiny features. I think another touch of warmth in the wood will be beautiful.

I love Julie's ideas of succulents , especially the pics with several different ones in the same pot . As far as the grey , I wouldn't -- you look like you like colour and excitement , so I'd go yellow on the pots -- a similar or slightly brighter shade then the cushion on the couch or chair to the left . It would tie it all in , and make that lovely mat look more like a feature too IMO . Without knowing 'the bigger picture' ( what else is 'happening' around that wall ) , just what I see I'd be inclined to add a light either side of the door too -- stick to the same shade as the joinery ( personally , I'd go for a 'clean rustic; style with say 15 squares each side ) , or if brave ( and assuming the guttering etc is probably a similar charcoal as your door joinery ? ) , go for the same yellow as your pots -- add a Wow !