EconoPundit has an article on the state of the Dollar, and a lengthy analysis of what, if anything, the current low value actually means.
There is far too much to summarize here, but I'll note one thing: The same index that shows a steady decline from a peak in 2002 looks bad. The expanded view, extending back to 1973, shows ups and downs, and we're at the low edge right now.
Interestingly enough, there was another period when the dollar was this weak. It was the economic boom of the 90s, which Democrats cite as a major Clinton success.
Correlation is not cause, but to me, it seems to be evidence that a weak dollar doesn't rule out prosperity and economic booms.