I just had to do the same thing with a second VGA monitor and a Sapphire 7770. Cheapest solution I could find (that would fit on the card with two adapters plugged in) was a passive DisplayPort to VGA adapter for US $8.24 new on EBay (PC Display Port Male DP To DVI Displayport Adapter
). Works great. If you need mini-displayport, I believe they have those, too.
As to which is best, I don't think it matters to an analogue monitor. However, if you ever want to add a third analogue monitor, I believe I read that one of the adapters has to be an active one.