Add the top & bottom ground polygons. If you have to cut a trace and add a wire, the ground plane will not make a difference. You could lay the 7805 flat on the board than and use the ground planes to help cool it.
The design needs some more caps - on the VCC, AVCC, AREF, and 22 pf caps on the XTAL1 & XTAL2 pins.
I see an ICSP connector for downloading a bootloader, or a sketch that starts in place of a bootloader.
I see a serial interface if you want to download a sketch that way via the bootloader. The pinout used is not standard. You might want to revisit that so you plug on a standard part like an FTDI cable or an FTDI Basic. If you're planning on making your own adapter cable you're all set.
A Diode across the pullup resistor will make for more reliable downloads,
Thanks very much for looking. I'll add the polygons.
I thought I had a cap on vcc but i'll add it. The resonator has the caps built in I thought.
Holy cow if that serial cable layout is wrong that's a big oops - it's meant to be the same as my RBBB - i'll get right on that!
whew: I'm pretty sure the serial connector is ok - it matches my prototype which works with the same cable as my RBBB. I guess it's not well labelled though - I'll add some clues for when I forget>
from top to bottom goes ground, skip, 5v, PC TX - AVR RX, PC RX - AVR TX, and RTS/RESET.