CHF is the strongest. NZD is the weakest. BUT....
The "but" is that that the market has not gone very far. The largest range for any pair is 68 pips for one of the major pairs (the GBPUSD). The lowest is the AUDUSD (37 pips). The EURUSD has a range of 46 pips (see lower chart).
The FOMC decision later today is the focus and the market action until that time will likely be from the flows. So that may be back and forth action like we have seen in most pairs today.
The strongest in the snap shot is the CHF. The weakest is the NZD. The dollar is up marginally vs. most currency pairs with the largest changes against the GBP, NZD and CAD.
It really is all about what is said by the Fed and the market price action. Even then, it might not be until January when we get a firmer idea of dollar direction as we hit the reset button and do the whole thing over and over again at each meeting in 2016. For today, you can look for a trade, but expect some ups and downs.