There are hundreds of sunless tanners on the market. My personal fave is Sienna X, I don't like St Tropez, I don't like the colour. But I don't believe there is a 'best' there is just the one that you prefer! Try a few, ask your friends, see whats available and give them a try.
Try Xen-Tan - they offer three ranges (Dark, Medium, Light/Gradual) so even the fairest skin can enjoy a natural-looking tan. The formula has olive undertones to it, so you can't go orange and you will achieve an olive sun-kissed glow. It is easy to apply, has a gorgeous fragrance and doesn't streak, as each product is packed with moisturisers. Hope that helps x