Some can save space if they are designed to connect to the edge of your desk, but you are only saving space under the monitors. If you want to be away from them more, then they either need to be wall mounted (move desk back) or you need a bigger desk.
LCD's are generally pretty good at allowing desk space, at least compared to their predecessors of CRTs.
But it does come down to the size of the monitors and what you are using your desk for / with. Personally, any desk that gets called a computer desk is a waste of time if you are after space. I have a old work desk / writing desk, it could nearly be called a small dining table. The original "computer desk" I had was a desk kit, and that was a waste, espically once I was no longer the 5" tall kid.
of course, at the end of the day, it depends on where you have the thing setup as mounting things on the wall does not work if renting or if you have to talk your partner/parents in to drilling holes into the wall.