Man, I was trying to make a cake picture kind of like this, and I know how hard it is to get it looking natural. This is really great! I like the lemon's transparency, even though it may be more stylistic than realistic. And I second timzero4's advice about scorching the meringue. The translucency really makes the pie look more realistic and yummy.
The crust is perfect although slightly too uniform. I'm jealous of the crust. If the meringue had some brown scorching on top and the Lemon filling and lemon slices were less "straight-edged", it would have been difficult to tell that this was CG (the displace modifier works well for that kind of thing). A few crumbs on the plate would have worked well also. Nothing in the real world is ever this perfect, not even advertising food. Otherwise, very decent rendering; good texturing and lighting job as well.
Yes, I'm aware there is glitches left. I'm not in the realistic 3D (even less in food rendering), this one was a first try. I'm not really happy with the crust, and I hesitate with the meringue, if I was to burn it or not. This model was made for some "speed modelling" mini-challenge, just for fun. So I admit I did not spend enough time refining the model. I spent more time on the shaders, discovering Cycles in the same time. I kind of gave up at this result, because my hardware does not allow more (I cannot use Cycles with my GPU, which is not compatible) and I needed my computer back