I actually am one of the few who believes that the USD is near to a major rally, so I'm wondering if that might have a slight bearish effect on Bitcoins relative to the USD. We aren't there yet though, but we'll just have to see if such a rally occurs how BTC reacts.
My thinking, however, is that the phenomina may be unrelated. Many assets go down when the USD goes up (and vice versa), but I think that's primarily due to the deleveraging/releveraging process. Nobody is borrowing USD to lever-up on Bitcoins, so I don't think they would be effected that greatly by a increase in dollar value.
The best argument for a long-term Bitcoin rally is actually fundamental. 21M Bitcoins is a very limited supply, so it doesn't take a huge amount of market penetration to revalue them much, much higher than today. Of course, like any market, it will be a rollar-coaster ride along the way.
So in conclusion I'm extremely bullish on BTC long term, but over the shorter term (a few months perhaps?), I'm waiting for some sort of a USD rally here just to see if there's any correlation at all with Bitcoin valuation.
What I'd really love to see is some momentum indicators on the charts to help time buy-ins
