Whatever you do dont use green ceramic tiles or red, pale blue is always good and if it's within your budget fibre optic lights, looks superb at night changing colours against the pale blue tiles,
I have seen many different designs, believe it or not Sandwash looks good, they use the fine grade and mix a blue paint in the mix, when it all dries out it the colour looks uneven but under water it give a good effect,
I think cost wise, sandwash is cheap to do, it's a long time since I've been involved I've lost touch on the prices,