My first reaction to this news is "uh, oh". I really think it's a contra-indicator to the health of the economy when companies are aggressively buying shares back. To me it implies that they're either a) not investing heavily in research, b) creating/exploring new markets, or c) finding attractive competitors to buy.
I'm sure each of these arguments can be turned around on me by the intellects here (which I enjoy). Heck, I can to. Aggressive buybacks, to me, just reeks of pessimism.