Louis has a nice comparison of McCain’s and Obama’s tax plans. He’s absolutely right that “trickle down economics” is bogus and wealth tends to just make more wealth for the highest incomes and that putting money in the hands of the poor means that they will tend to spend it:

For all of McCain & Palin’s bluster about Obama raising “your” taxes, the proposals are pretty clear:
Obama is proposing hefty cuts to the middle class which taper off as
you reach $250,000 a year; he then starts raising taxes, those hikes
becoming notable at the half-million mark and above. McCain, in
contrast, wants cuts for everyone but gives the lion’s share to the
wealthiest Americans. His cuts for lower and middle class Americans ($0
to $100,000) are less than Obama’s. Where Obama wants to tax wealthy
people, McCain wants to give them yet another tax cut, and reserves the
biggest windfalls for the richest people.

In that sense, their plans are diametrically opposed: Obama proposes
a 5.3% cut for the poorest Americans which reduces to 0% around a
quarter of a million dollars, then rises to an almost 8% rise for
multi-millionaires; McCain gives the poorest Americans a paltry 0.2%
tax cut which gradually increases with income until you see the
wealthiest getting a 3% cut.