One thing worth pondering (I'd have thought) is, if you are planning on getting any more lenses in the future (or upgrading the one you have now) and you know what that lens might be, check if the filter size on that will be larger and get the filter for that now, and a step down ring.
Say for example you fancy getting a sigma 10-20mm down the line. The size for that is 77mm I believe. So you could get a 77mm 10 stop and a step down ring to your 52mm.
When you get the 10-20mm lens (for example) later you are good to go from the off.