I would take the one with more ram since you cannot upgrade the ram in the future. The i7 is clearly a better processor but double the ram easily makes up the difference.
If you're going for a refurb, you might be pleasantly surprised -- I ordered option 2, and ended up getting an i7 for free, so got the best of both worlds.
Even though option 1 has a 2.8GHz Dual-core Intel i7, while option 2 has a 2.6GHz Dual-core Intel i5 would you say that 16GB RAM of option 2 plays a more significant role than the processor speed and intel i7 of option 1?