http://protea.worldonline.co.za/default.htm - protea atlas project. All kinds of information on South African proteaceae, including pictures, instructions on growth (by location, even), information on native habitat, distribution. The whole works.
http://www.protea.com.au/ - proteaflora website from Australia. Good bookstore, information on species with checkboxes for certain criteria such as drought tolerance, frost tolerance, soil type, etc.
http://www.australianplants.com/ - Australian Native Plants website. Jo O'Connel is an Australian now residing in Ojai, Southern California. The nursery offers tons of plants at the nursery itself, and also ships to a number of nursery's around the area. The website has been recently updated, and now has an availability list (sweet!), plus growing notes and a bookshop.
http://ezinearticles.com/?The-Protea-Family-(Proteaceae)&id=1809 - general overview of the Protea family, including cultivation tips and a brief overview of the various genuses
http://www.ipa-protea.org/ - International Protea Association website. Limited information, but does have a protea locator that shows blooming times for certain species.
http://www.californiaprotea.com/ - California Protea Growers association website. This seems to be more for cut flower people, but there are still some good links and information here.
http://www.silverhillseeds.co.za/ - Silverhill Seeds. This is the preeminent site for buying seed for hard to find proteas.
http://www.finebushpeople.co.za/ - South African website on proteas, with seeds for sale, books, growing instructions, etc.
http://www.nda.agric.za/docs/Protea2000/contents2000.htm - International Proteaceae Register. This has lists of scientific names, including where cultivars and hybrids came from, who names them, plus some basic information on the species.
http://www.anbg.gov.au/images/photo_cd/proteaceae/ - Photos of dozens upon dozens of protea species.
http://users.bigpond.net.au/macarthuraps/Images.html - Images of many of the hybrid grevilleas.
http://www.anbg.gov.au/telopea/telopea.html - Information on growing Waratahs (Telopeas)
http://www.pacsoa.org.au/palms/index.html - Information and pictures on almost all of the palm species out there.
http://www.plantapalm.com/vpe/photos/vpe_photos.htm - Pictures of over 100 palm species, along with cultivation information and native habitats.
http://www.palms.org/cgi-bin/ikon/ikonboard.cgi - International Palm Society message board.
http://www.bamboo.org/ - American Bamboo Society website. All sorts of information, including books, an extensive species list, and general information on bamboo.
http://www.abssocal.org/ - Southern California chapter of the Bamboo Society. Information on numerous species, galleries, and list of local bamboo nurseries and their respective services.
http://www.tropicalbamboo.org/species.htm - Information on many of the tropical bamboo species.
Flowering and Ornamental Trees Websites
http://www.tfts.org/ - Tropical Flowering Tree Society website. Excellent pictures of many flowering trees and shrubs. Also has a list of events for South Florida.
http://www.forestnursery.com/pricelist.html - Hawaiian nursery with many interesting hardwood and flowering trees.
http://mgonline.com/trees.html - Information and pictures on many different ornamental trees.
http://www.fernfactory.com/ - SoCal nursery specializing in ferns, including rare tree ferns and staghorn ferns.
http://spectresjungle.com/ - It's pretty much my favorite website.