Exactly this minus the cell phone. No reception where I ride once I'm 3 miles from the house.

Seat Pack:
2 CO2 cartridges
Patch kit
1 Tire Lever
Crank-Bros multi tool
Phone
ID
Emergency Money

Jersey:
1 or 2 tubes (depending on distance)
Gels (cherry lime Roctane usually)
Maybe a bar or carby snack

Blackburn seat pack,
2 tire levers
patch glue, patches
small bike multi-tool
2 spare batteries for flashers
2 Cliff bars

Jacket back pocket
4 cliff bars
ID
spare money
iphone (ID is rubber banded to iPhone)

Tights
house key (most important item!)

On bike
2 28 oz water bottles (don't like camelbacks)
rear fender, 1/2 the front
front and rear lights
horn
air pump

On head
helmet
glasses with retaining strap to keep tight to face (super important)

In the saddle bag are $10.00 ,3,4,5,mm allen keys , chain break , spare tube , rag , piece of tube for boot , house key

right jersey pocket spare tube , 2 co2's plus inflator , middle pocket cell phone , permit , cliff bar(s)

left pocket , Ruger LCP in holster :eek:

If my jersey is really loose or cheap (like a primal wear one I used to wear), then it did feel very heavy and like it was pulling down.

But with my better jerseys I can't even tell anything is back there. I've even stuck an extra water bottle in my pocket and forgot it was there.