Buy two decks from the same set. It will be more fair for all parties involved and easier to find cards that go together. Get different decks though. What fun is it if you know your opponent's strategy? I suggest you wait a few weeks until Lorwyn com...
The chances are actually slightly worse with multiple decks. The chance of pulling a royal flush at random from a single deck is approximately 650,000:1. 52/20 * 51/4 * 50/3 * 49/2 * 48/1 = 649,740 The chance of pulling a royal flush from a set of 5 ...
There's no real easy answer to this question. If only because right now, Standard is among the most "flexible" formats. Mostly in terms of there being no one best deck, and several very good decks. Both Solar Flare (W/U/B) and Angelfire (W/U/R) are v...