Hi,
Correct me if I'm wrong but aren't those two chips (MCP2200 and MAX3421E) two different things?
The MCP2200 seems to be like the ever so popular FTDI232, ie it acts as a USB device. The MAX3421 however seems to be a USB host to which you connect a device, like a thumb drive or whatever. Actually it seems like the MAX3421 can act as either device or a host.

/Henrik.

EDIT: Ah, OK you noticed that while I was typing....