I feel like it's definitely going to go up and up at least for a short while-- but there's always the possiblity of a crash, one that the bitcoin might not survive. I'm pretty confident that even if the bitcoin currency itself goes under, eventually a stronger version of the same idea would take it's place and succeed. It's just got too much going for it to ever just fade away.
The only thing I see that can destroy the value of Bitcoin is something that undermines the security of the actual Bitcoin network, which is why I mine. It's properties make it too damn useful for too many people otherwise.
It can survive a speculative crash. I don't think it can survive a technical flaw.