You say that like there's something inherently wrong with a weaker dollar. First of all, bear in mind that the dollar still beats many other currencies in other countries. But beyond this, if the dollar weakens, then travel to the US and the purchase of US goods suddenly become more appealing to foreigners. Think about it if you're a European; your Euro now goes further than it ever did before. Maybe now would be a good time to travel to the US and use that money while it's good, and maybe buy an iPod or a laptop, or something else that, even with duty fees, is way cheaper now than it would be back in Europe (I know several people who have done this just this summer). Meanwhile, people in the US are less likely to buy imported goods, since they're more expensive. This increases the amount of money in the US economy, which is usually considered a good thing (since it comes from real value, and not just printing money).
Also, I'm fairly confident that there was fairly massive deflation during the Great Depression. So, that argument doesn't really hold up either (unless I'm misunderstanding it).
I'm not arguing the point that Bush has been a horrible President. But let's keep ourselves to important criticisms, and not get caught up in inflation arguments.