The dictionary definition of liberal uses descriptions such as "broad minded," "not bound by authoritarianism," "generous," and "tolerant."   Not exactly pejorative terms.  I'm a "liberal" and quite proud of it.  It's unfortunate that the word "liberal" has become a dirty word, and not not what it used to mean colloquially.
I'm afraid I have to question the idea that tax cuts for the wealthy are more of a stimulus than for the lower and middle class citizen.  Approximately two thirds of the US economy is consumer driven, and there are far more lower- and middle-income Americans than wealthy ones.  They're the group that's going to spend any tax rebate almost immediately, and not the rich.  The rich spend money whenever they want and not because of a tax break.  They can do that because they're rich.
As far as business investment goes, tax breaks have very little effect.  I can't think of many small or large businesses that plan their development strategy based on a tax break, or the promise of one.  This isn't solely my opinion.  It's also that of President Bush's first treasury secretary, Paul O'Neill.  He oughta' know; he ran Alcoa for over a decade.  (O'Neill was also known as   being probably the most intelligent person in Bush's cabinet during his first term.  Characteristically, he along with the other moderates like Christie Todd Whitman and Colin Powell were marginalized almost from the start.)
It's true that Medicare and Social Security are expensive entitlement programs.  It's also true, I think, that they've substantially raised the quality of life in this country, which is something that government, as an entity, ought to be about and focused on.  Actually, there would be ample funding for both programs if we weren't flushing $1.8 Billion a week into the sinkhole of Iraq.
  
Lawrence Lindsay, Bush's economic adviser in 2002, was savagely attacked by the administration for daring to suggest that the occupation of Iraq -- and that's what  it is -- could cost up to $200 Billion.  What an irony, considering that current upward estimates are now around $2 to $3 trillion.  To put that in perspective, the gross domestic product of the entire country was $13.8 Trillion last year.
It won't be Medicare and social programs that break the back of the economy, or future generations of taxpayers.  Now, and for some time to come, it will be Iraq.  All of this -- the astonishing costs, the dead  and maimed US solders, the more than 100,000 Iraqis (about half of which were children under the age of 18 years old) killed -- might have been avoided if the commander in chief had been a more open-minded, questioning, tolerant, and less ideologically bound person.  But that would smack of "liberalism."  And we don't want that, do we?