$100k is more than enough to sustain two founders for a year. Especially if the founders happen to be young and unmarried. If they were living together they could probably make it on expenses of $50k for a year while still living relatively comfortably (even at Silicon Valley prices).
Also, I'm not sure what to make of your comment "Two strong hackers, working for 6 months is eaily $140K expenses" How good the hackers is hardly related to the expenses they require. Perhaps 140k is the opportunity cost?
Having enough in the bank for 1-2 years is probably a good idea, but it sounds like they could do that on $250k-$350k.
Also, I agree with matt, focus on the percentage you are giving away rather than the amount you want to take.
At $50K your taxes are going to be pretty low, but just the same try and have the company pay for things instead of buying them with your salary.
If you look around you may find a business partner who could give you some money as part of some kind of deal. Traditional software companies can do this by pre-selling licenses at a discount and web companies looking for ways to get more users may pay you if you find a way to help your users get signed up with them. However I'd caution against spending too much time on this sort of thing yourself as it can easily become a distraction.
Also, I'm not sure what to make of your comment "Two strong hackers, working for 6 months is eaily $140K expenses" How good the hackers is hardly related to the expenses they require. Perhaps 140k is the opportunity cost?
Having enough in the bank for 1-2 years is probably a good idea, but it sounds like they could do that on $250k-$350k.
Also, I agree with matt, focus on the percentage you are giving away rather than the amount you want to take.