I think there is no reason for us to panic. SEO will be there as long as there is Internet and websites. And read and understand the article first.
SEO will not die, infact will evolve,change eventually. see what matt cutt says: http://www.mattcutts.com/blog/ But Google Instant will impact SEO to a certain extent. It might change the way keyword research is being done. Performance of long tail keywords might be affected, but not always, in every case. PPC might also get affected. We can at this stage, only assume a few things. You can better judge the impact after a few weeks. He is an article explaining how this might affect long tail keywords http://searchengineland.com/will-google-instant-kill-the-long-tail-50110
Not everyone searches the internet the same... There is a little effect, but not much and there are definitely some SEO techniques that we can use to better our results because of the "Real Time" search.
SEO will always exist, but how it exists will change, FB will become the top site used for searching soon but G will bounce back with new ideas
Paraphrasing Mark Twain: "The demise of SEO is greatly exaggerated". Every time that Google changes its algorithms we get the same story...and now with Google Instant. No problem with me, if people abandon because of these stories I'll have less competitors...
I would put more effort into link building and producing good content, this will do 2 things. Google exist to find good content and it will always be that way. Plus the referral traffic is a bonus. Also you may want to develop some keyword diversification that will be easy to do if you are building good one way links from relevant content.