Search is far from archaic. It's here to stay. Even if Xobni or Facebook figure out how to make useful suggestions by predicting my intentions (something I doubt would work very well, no matter how much they know about me), it would have a near insignificant impact on the utility I get from Google. People will always want to search for information and unless someone figures out how to build a better search engine than Google, Google will remain king.

With regards to new interfaces (voice/visual/whatever) that people sometimes say will be the "next big thing" in search -- these are just features that Google can easily implement if they prove to be so effective (which they probably won't -- I'd much rather type in my query than say it). Replicating the sophistication, performance and scale of Google is much harder.