I like just
McPain
(I can’t find a catchy concise rhyme with “Death unto those who question the rightful and peaceful and prophesied accession of Lord Obama!” without using “baby Mama” and that might be seen as offensive).
McCain/Palin
The Pair to Nowhere.
Or a in the tradition of the Christian/Darwin fish, a barracuda being swallowed by an American flag.
Or a pit bull with lipstick encircled with a red circle/slash.
You’ve got that backwards - the barracuda should be shitting out the American flag.
Sarah Palin - She even craps patriotically.
Oh that’s beautiful!
P.O.W.-Woman
Who cares about the issues?
Or if you wanted to go dirty: a graphic of a barracuda on top of a geyser with the phrase “OLD UNFAITHFUL and the NORTHERN LIGHTweight”.
Or a pic of McCain next to the Palin swimsuit photo with
We Need a Chief, not a POW-WOW
(Golf clap)
“For 5 years he couldn’t have a woman, let’s give him at least four!”
-Joe
“Happiness is a Lobbyist Sellout walking Home
With a Pitbull under each arm.”
ANNOY THE MEDIA. VOTE FOR OBAMA.
Either that or my sig (which I stole from the internets).
“Four more years!”
McCain/Palin: The only real change you’ll get is climate change!
“No way, no how, no McCain/Palin”
How about:
THEY DIDN’T SMOKE LOADS OF POT.
McCain/Palin
When you’re rich enough to pay the very least.
Here’s the one I made on CafePress–it’s going on my car tomorrow… 
My car would get keyed in about .03 seconds flat. I don’t think I have those kind of cojones!
McCain/Palin
Change means Lying. We’ll do it best.
My car has bullet holes in it already–I can leave it unlocked, windows down with a crate of brand new iPhones in the front seat and nobody will touch it because it looks like a crazy drug dealer’s car. I sincerely doubt a few key scratches would even be noticed!
My car is the embodiment of Paul’s Law–“You can’t fall off the floor.” 
Prisoner Of W.