Here is the list of pages and associated forums I usually visit for latest happenings among 3D printing enthusiasts (in no particular order):

https://duet3d.com/

http://reprap.org/

http://forums.reprap.org/

https://miscsolutions.wordpress.com/

http://www.sublimelayers.com

http://forum.seemecnc.com/

https://forum.e3d-online.com/index.php

https://groups.google.com/forum/?hl=en&fromgroups#!forum/deltabot

http://blog.rymnd.com/

http://www.kosselplus.com/

https://www.hubs.com/knowledge-base/key-design-considerations-3d-printing/

For Reviews and general 3D trends:

Thomas Sanladerer’s youtube channel: https://www.youtube.com/user/ThomasSanladerer

http://www.3ders.org

Shopping links (apart from ebay and amazon):

http://e3d-online.com/

https://duet3d.com/index.php?route=common/home#products

https://www.ultibots.com/

https://www.dold-mechatronik.de/

http://www.motedis.se/shop/

http://www.robotdigg.com/

http://3d-grottan.se

http://www.3dprima.com

http://reprappro.me/

https://clever3d.de/

Repository of 3D printed parts:

http://www.thingiverse.com/

http://www.yeggi.com/

https://www.youmagine.com/

Educative links for kids:

https://www.hp.com/us-en/shop/tech-takes/3d-printing-glossary