In addition, though the known solutions (at least known to me) to a 51% attack (from a motivated attacker with significant resources) are pretty awful, it's not necessarily the total death of Bitcoin. So while it would be a severe blow (as the block chain split was, as the recent price crash was), I would expect Bitcoin would survive somehow. Bitcoin's death has been predicted so many times and Bitcoin has weathered crises.
From my own perspectives, the block chain split was of zero consequence. If it were not for the activity on this forum at the time, and my interaction with this forum, I (personally) wouldn't have even noticed. The same would have been true for most users who either don't spend bitcoins on a daily basis or don't fret over the time to confirm. Once users are competing for blockspace, a 24 hour long time to confirm will become more commonplace for much more mundane reasons. And the price crash wasn't even the worst crash that I've seen since I've been here. On a percentage basis, dropping from about $250 to about $50 over the course of a week or two isn't as bad as dropping from $32 to $2 in 2011 (2012?), although it happened much faster.