You may have seen these or if not look online at http://www.london2012.com/
I like them all. I have had a good look at them and even online they look really interesting. I cannot tell how big the wording is at the bottom that identifies them as to do with London 2012, but it doesn't look very large.
I have ordered three for work. This was hard as I tried to decide which ones they would like, which might not be what I would like! I have chosen the swimmer with the Olympic rings, (obvious) the word GO over a stopwatch (pop art style) and the RoseRose one as I like the soft colours - even if it isn't obvious how it relates to the Olympics without reading the blurb!
I looked through all the posters they have in the shop and it is interesting to see the London ones for 1908 and 1948. Very traditional and of their time and both show Parliament. We wouldn't be showing that building now, not after the expenses scandal.
The shop also sells ones from around the world for the Games of the twentieth century and you can see how designs and tastes change. There is even one with them all shown, but lots of other people must have liked that too as it is unavailable.
It will be interesting to get reactions!