this is pretty good. my critique is the top bun doesnt look puffy on the sides. looks more like a cyclinder with the edges chamfered/beveled. The lettuce feels a bit artificial because of the shape of the surrounding edge. But i have to say most of the materials are pretty spot on, except the patty.
under $2 at Burger King! But really, looks good. The cup lip really comes out, but not too far, which is what makes it great. Neither did you give the background too much depth. As for appetizing, that burger looks plastic. Not to say it is, I don't really know, but it's colors are maybe too vibrant. That over coloring/ overly perfect look to the new HD might find some trouble in the food ads. Great subject choice and well done(haven't checked out your gallery yet to see if food art is your specialty or something) but especially if this is one of your few attempts into the inanimate/3d food matter, your thumbnail really caught my interest when I searched '3d.'
Ice cubes are really cool. Which GI simulation plug-in did you use? According to my experiences i can say that this looks like Maxwell, but on the other hand it looks a bit like V-ray.. hmm, i am not really sure.