I have roughly (because they don't stand still to let me count):
20 Black Sex Links
20 RIR
40 Marans
10 Speckled Sussex
10 Dark Cornish
10 Jersey Giants
20 Barred rocks
It's obviously impossible to tell for certain which egg comes from which chicken, but in general I find the Black Sex Links to be the best layers. Several of them are kicking out double and triple yolkers as well, which we love for our own breakfast.
I think they are all fine layers. You can tell the Cornish eggs, because they're more medium/large size than large to jumbo. The Sussex lay pale brown eggs which are of good size. After that, though, it's pretty hard to tell who's laid what. Some of them are kicking out very pretty speckled eggs, too. The marans are just coming into lay now, and I've found some dark and speckled peewee eggs laying about on the ground.