I just did that (after a long time) and was amused to see that my highest rated photo of all is currently this one:
Photo © Paul Markman
This has a rating of 4.82, with 11 votes.
I like to think that I submit photos of a decent standard, but by no means can this surely be considered worthy of attracting the attention it evidently has amongst voters. It has only been viewed 400-odd times in total. Equally, in the past I have seen a couple of my photos previously well rated suddenly drop significantly, which can only be accounted for by the fact that they got a few really low votes to make such an impact on the overall average.
You may recall this thread which caused something of a stir, to say the least. I have no desire to open up elements of that debate again, but buried in there were some interesting points and I am interested to follow up whether there have been any subsequent thoughts about making any changes to the voting systems that were discussed then (not just for Photographer's Choice).
Not a big deal for many, but the site still reserves space on its Home page for 'Top Rated Photos' and thus this theoretically is a way for photos to get more exposure. That said it seems to me the feature has not been working properly for ages now (as it lists all photos in the database, not just those rated above a particular level in the 'star' system).
Whilst on the subject, it might be interesting to know what your top rated photo is, and whether you are surprised or not to see it rated as such.
All the best.