With the focus on Pryor and Sykes over the last few months, Neil Gorsuch come as a bit of a surprise (although he has been on the short lists of potential replacements for Justice Scalia's seat).
The head fake was William Pryor being seen recently at Trump Tower (with Trump stating right after that he was ready to make his pick). Still, Gorsuch would be an appropriate choice. If Gorsuch is Trump's pick, it shouldn't be that much of a surprise.
Update: Politico: Trump deciding between Gorsuch, Hardiman, and Pryor (with Pryor fading) and CBS: Gorsuch or Hardiman and NRO on why you should not count out Hardiman
Volokh Conspiracy: How President Trump will shape the federal courts
Washington Free Beacon: Trump may appoint Gorusch to SCOTUS