Here are 6 of my favourite highlighters, I have a few more to add to this as I originally did these swatches last summer.
Emphasize is the subtlest highlighter i own, applied lightly it just gives a lovely sheen rather than glitter. This is perfect for when you don't want it to be obvious you have highlighter on but still benefit from the effect of it.
This is a gorgeous creamy golden colour, it's very pigmented so a light hand is required. I also use this an eyeshadow sometimes.
This is just a gorgeous peachy/pink highlight. It's not available at Mac at the moment but Accessorize have a merged blush that is very similar.
I love the Illamasqua Illuminators, they don't contain any glitter at all they just have a gorgeous sheen to them, Odyssey is a gorgeous silvery white that works really well on pale skin.
Poised is a gorgeous pimk highlighter, its similar to Benefit's High Beam but I find it much easier to use and prefer the overall effect.
Shell is a lovely subtle highlighter, I have really built up the swatch here but applied lightly it just gives a beautiful golden sheen.