I think bitEur:bitUsd pair would be interesting...I am hesitating to convert my BTS to bitEur at the moment because 1) the back and forth of checking if biteur is at fair price just confuses me 2) not much liquidity for biteur 3) I hesitate to sell my BTS for an iliquid asset such as biteur.
But if I can trade directly biteur for bitusd I can only check this exchange rate which I am familiar with, it will increase biteur liquidity,avoid the back and forth for checking the price, I would be less hesitant to exchange my bitusd for biteur, I will be able to do the normal fiat exchange without risking my BTS potential upside.
Bitusd:BitBTC also will be obviously interesting.