I don't have particular must-read sites so much as collection of sites with potentially interesting material set up in Pulse which I scan through twice a day or so.
I end up reading stuff from HN [1], The Verge [2], Wired[3], A VC[4], VentureBeat[5], AllThingsD[6], Technology Review [7] and Ars Technica [8] most often.
They aren't strictly digital related, but I get a lot out of Archinect [9] and core77 [10] for design interest.
http://www.contemporist.com
Daily routine because of my obsession with architecture, home design and styles.
http://www.reddit.com/r/ArtisanVideos/
Hours and Hours of video on how things are built, by hand. I'm utterly fascinated by the craft of building tangible objects with your hands.
Reddit, for starters. There are a lot of great sub-Reddits you can subscribe to and you can remove a lot of the pointless default ones (/r/atheism, /r/politics, /r/aww, etc.) so you end up with a feed that really suits you.
http://inbound.org/ is basically HN for people also interested in online marketing, SEO, etc - lots of great practical stuff ends up on there that never makes HN.
I use Flipboard to aggregate the best stories from several sources. They have a heap of design feeds already listed as well as business, tech and HN in there too. Best part is its easy to flick quickly through headlines, share what you want and also save to instapaper for later.
1. Quora - To participate in discussions and learn new things
2. http://zenhabits.net - Minimalism and Better habits
3. Reddit/r/Science
4. Techcrunch, GigaOm, Engadget - Tech Trends
5. Fubiz.net - For daily dose of inspirations
I used to keep up with tens of blogs and sites via RSS, as I got busier it became obvious I couldn't possibly keep up with all of them. Now HN & NYTimes is the only place I visit and occasionally Lifehacker. HN filters out most of what I don't care about.
O'reilly radar - 4 daily links is what I read when I don't even have time for HN. If it's one of the things I really care about, it usually ends up on there. http://radar.oreilly.com/
I use Prismatic (http://getprismatic.com) which gives me more than enough to read on a daily basis. I also use Zite on my iPad (because Prismatic doesn't have an iPad app -- yet?).
I went over to Pinterest and took a look at the popular and found nothing worth looking EVERY DAY. That's when I realized you said PinBOARD and not PinTEREST.
I stopped using Dzone ages ago. It has become a mixture of spam and dangerously stupid disinformation. It's being heavily gamed and the owners don't care.
I end up reading stuff from HN [1], The Verge [2], Wired[3], A VC[4], VentureBeat[5], AllThingsD[6], Technology Review [7] and Ars Technica [8] most often.
They aren't strictly digital related, but I get a lot out of Archinect [9] and core77 [10] for design interest.
1: http://news.ycombinator.com/newest, 2: http://www.theverge.com/, 3: http://www.wired.com/, 4: http://www.avc.com/, 5: http://venturebeat.com/, 6: http://allthingsd.com/, 7: http://www.technologyreview.com/, 8: http://arstechnica.com/, 9: http://archinect.com/, 10: http://core77.com/