A 15% spread in 48 hours. That is not 'stable'.
5 * 0.15 = 0.75
The most wild of the swings were 5.13 and 4.78. 5.13-4.78 = 0.35
However, you cannot count the wild swings because they last moments and half the time Gox doesn't fill out people's orders and so you can only count on what the price been most of the time, which has been from 4.86 through 4.96. That's about 1% movement a day
If this is too technical, look at http://mtgoxlive.com/orders?volumeon
Does it look like a tornado going all the way up?
In the last 96 hours it has been basically around 4.90 and not moving except one attempt at a rally that the manipulator crushed so he could buy cheap coins. (4.90ish is a good low price to buy them the way things are going).
Basically the price has stagnated. This is bad for speculators because if it swung from 5.00 to 6.00 every day and back and forth it would be far more stable than jumping somewhere and stagnating. You could be all "Oh it will be back to X amount in a day so no worries, I can price my products based on this."
Instead it jumps, then it stagnates for days, then it jumps and stagnates.