DP Review - has, for a very long time, been the best, most comprehensive, place to find reviews of cameras. It is owned by Amazon, but seems to have remained clear of any editorial influence. The reviews tend to be very detailed, and can often be 'topped and tailed', with just the introduction and the conclusion giving sufficient idea of whether or not you should look further.
flickr - is a very well established social, Web 2.0, photo-sharing site. I don't know if it is the best but, without long explanation, I think it is the most 'middle of the road'. In other words, I think that if you want to share photographs, it is likely to keep most people happy for most of the time. I have learnt a lot from the comments of others, and probably even more from trying to make comments on other peoples' photographs.
1x - for those wanting a consistent diet of more aspirational photography this is an excellent web site. The content is curated, meaning that you canot freely post shots as any submission needs to be approved.
Martin Bailey - is a photographer I admire in many ways. i would say that his photography is technically perfect, but he also publishes a very informative podcast, has a tremendous web site which can take you away for many hours, and so much more ... but he is also a top bloke, and that is communicated in all that he does.
Google Nik Collection - others might think otherwise but I think this is the best software if you develop even a very small ambition to 'play' with photographs and apply special processing treatments. I especially like the Black & White processing tool, Nik's Silver Efex Pro. Best of all! It is now FREE!
Digital Photography School - truthfully, there are dozens of sites out there, offering advice of all sorts, but I happen to think this is one of the best. I might be biased by the fact that I have some of my writing published by them, however it is one of the longest established photography web sites, and a quick search always turns up a lot of interesting things.