Ned wrote:
Since when were tax cuts universally based in the supply-side?
I recieved a $300 rebate cheque, and yet I don’t think I qualify as the “supply side.” 
(nor do the “rich,” for that matter)
I wasn’t aware that this was a proven proposition.
By “improvements in infrastructure,” I assume you mean wasteful government bureaucracy that passes for infrastructure. 
The assumption here seems to be that creating infrastructure (and therefore jobs) promotes growth, but lost in this reasoning somewhere is the fact that jobs and production are just a means to an end on the larger economic scale–that end is profit, and therefore, economic growth.
Money can only ripple throughout the economy if it serves the ends of profit, not government–because when government invests, it generally recieves no return on its investments except what it recieves in taxes–which are themselves just the fruits of private economic gain, ultimately.
I think deficit spending can help certain sectors of the economy, but that it is a tool for general economic improvement is, well, crazy–the underlying proposition is that we can win the economic “game” without trying to score any goals. 
I tend to agree that we should attack the problem of sagging demand where it exists, not just anywhere. Definitely, in our current economy, demand is sagging on the consumer front (hence, a glut of production assets).
I’m not actually a trickle-down stalwart; I think that trickle-up–namely, tax rebates to the appropriate demand-side parties–is most prudent.