You've got to be blind if you can't distinguish between the two main candidates.

One is a self-declared "War President". The other only wants to use war "As a last resort".
One has racked up the largest single-term deficit in history, more than every president in history combined, and still wants to cut taxes further. The other wants to balance the budget, and will raise taxes on 1% of the population in order to try and do so.
One badly wants to privatise Social Security. The other strongly believes that would be a mistake.
One wants to protect drug company profits. The other wants to protect the free market economy.
One wants to create the first amendment to the Constitution that would explicitly remove a right in order to deal with an issue whilst the other believes in state's rights.
One believes the War on Terror (tm)(R)(c) is useful to explain away an invasion of a sovereign nation, the other believes that it's about catching Osama Bin Laden and preventing further terrorism.

They're chalk and cheese. If you really think that Kerry is so similar to Bush then I guess the RNC spin doctors have earned their money.