Let's see here (Warning: Gonna be a long post):
Stickers:
Department sticker in rear window (lower left)
EMT/Firefighter sticker in rear window (above center brake light)
FF Calvin urinating on fire in rear window (lower right)
Remeber 09/11 with American Flag in left rear vent window
IAAI Member in left rear vent window
NREMT in right rear vent window
NAEMT in right rear vent window
IEMSA in right rear vent window
WA EMT in right rear vent window
Communications:
Bag phone mounted in vehicle
Kenwood TK-706G 128 channel mobile radio
Radio Shack Pro-2067 500 channel, 800MHz Trunk Tracking Scanner
Three additional visible antennas and one hidden
Lights (currently all amber unless noted)
Clear side handle spotlight (driver's side)
Whelen Flatlighter Strobes (Front passenger visor)
Clear corner strobes powered by 6 head, 90W power supply from Whelen
Whelen Dash Misers x2 (upper rear window, left and right side)
Multi pattern headlight flasher
Taillight flasher
Jump Kit
Jump Suit
Two emergency blankets
Portable compressor
Flak Jacket
Spare coat and gloves
The rest of what I have is not fire/EMS related. Most of what I have installed, I installed at my previous department but am not allowed to use them where I'm at now. I've removed the back seat and cage that I had installed for my dogs (well, the upper half anyway). I've also tinted the rear windows to the maximum amount allowed to cut down the profile of the installed lights. They still work just fine when turned on, but when they're off you have to know what you're looking for to see them.
Oh yeah, I drive an all white Chevy Caprice. (It's no wonder nobody wants to pass me on the interstate.

)