Thanks for your supporting input on this, Rob.
I think the total no. of pic's in 'Urban, Abstract + Still Life' is relatively low
because it's off-putting to use this combined category the way it is. I think that if it is split three ways, then more people will be keen to upload these types of photo. Abstract and Still Life are only similar if you don't care much for either
I agree that Abstract is perhaps the least popular, but it is a good catch-all category for photo's that perhaps don't fit into any other category, so I think it needs to be on its own. As does Still Life, definitely. And Urban too!
I agree with Rob's suggestion for a Macro category as well, as this is becoming increasingly popular.