My boyfriend is coeliac and there aren't many cakey things we'll both eat as I'm not a huge fan of the texture of many gluten free things! But an adaptation on this chocolate brownie recipe makes a really good chocolate cake:
www.dovesfarm.co.uk/recipes/gluten-free-chocolate-brownie?offset=1
If you halve the sugar content (so 100g instead of 200g) and use half and half gluten free flour and ground almonds you get a really nice, moist, light chocolate cake
You would never guess it was gluten free! And it's (marginally) healthier than the original brownie version of the recipe.......
Looking at the recipe again I've just noticed that when I made it on Monday night I only used 100g of chocolate instead of the 150g - oops! And it was still really good 
The shortbread recipe on the Dove farm site is really good too.