Seeking critique on First PCB

Hey guys,
Attached is an image of my first design in Eagle.  I'm a complete noob at PCB layout and an amateur at electronics in general, so I'm prepared to be brutalized.  Any comments general or specific would be much appreciated before sending this off and twiddling my thumbs for a few weeks. 

Its a simple circuit, it uses a Teensy3.1 microcontroller to control an i2c expander driving 12 reed relays, with another i2c expander handling simple inputs.  There is also a Midi I/O circuit with optoisolator connected to one of the Serial busses. The 2x13 headers are meant to connect to a DB25-IDC connector, to save me PCB real estate and cost.  I know it looks like a lot of wasted pins, but this is all designed to interface with an Avid Profile live mixing desk, so I'm working with their GPIO pinout. 

The bottom layer is entirely a ground plane and the top layer has a 5v rail along the bottom and of the red traces larger than 10mil are power. 

One of my main points of uncertainty is the power layout.  Would it be better just to do a copper pour over the entire top layer?  Or should I keep it as is and add more ground plane on the top layer? 

Anyway, like I said I'm a beginner so don't hesitate to mock my horrific layout
Thanks!
Adastra

Does it pass DRC? Several bias look shorted to pins.

pins on the 8pin dil chip seems to be too small and maybe misplaced.

Hi Adastra,

in my opinion, you should rethink your component placement first. I edited your screen shot to show some things I would change:



The orange rings mark spots where you left very little clearance. The mono jacks might already touch the array of reed relays. This also applies to the Serial / GPIO expanders and the Teensy. Depending on the size of your heatsink, it might short the SPI connector.

The direct connections of the ULNs is cool but I would give it a bit more clearance as well. In case you will need to redo ULNB, you will reflow the pins on MCPA and probably burn the cases of the reed relays 

I also marked some spots where you left some place, I would rather use to get some more clearance on the board. See green markings.

There is an airwire left on the Teensy as well.

Best,
Carsten

Thanks everyone.  I'm afraid I've already sent it to OshPark, but I suppose there is a first time for everything and I'll have to live with my mistakes.  I did makes changes to the original here based on feedback from another forum, and some of those overlap with what you guys mention.  I did increase the drills on all the through hole parts.  I did use the OshPark DRU file and checked ERC and DRC for what its worth. 
You guys have we worried about clearance issues, so we will see.  The gaps on the far left and right are for sliding into a hammond enclosure built for the purpose. 

Anyway, if it works out I'll count myself fortunate and if not I'll certainly apply your comments to Ver2.