The board. It's difficult to see some of the chip information because the silkscreen came off along with the thermal pads.

Here's an idea of where all the chips reside in relation to one another:

Apple A4 Processor

Samsung NAND Flash

Empty spot for another Samsung NAND Flash???

Apple 338S0891 Power Management (Likely)

Broadcom BCM4329XKUBG IEEE 802.11 a/b/g/n MAC/Baseband/Radio w/ Integrated Bluetooth 2.1 Transceiver