I love RSS feeds. I follow way too many. Here's a top 5 i'm enjoying at the moment:
Austin Kleon's Scrapbook blog: Austin already has a a great blog of his own work, but he's also got a tumblr feed where he posts interesting and inspiring stuff he finds.
XKCD: Don't let the simple stick-figures fool you. This is one of the best online comic strips today. Make sure to hover your mouse over the image for the alt text closing words.
Derren Brown: Illusionist and painter. What makes his blog great however is that it doesn't just cover magic and painting. He has a very dedicated team (predominantly two called Phillis and Abeo) who post numerous interesting articles across a range of curious topics.
Parka Blogs: A great art book review site. What separates his review style from most is the amount of images he posts of the pages alongside a video of actually flipping through the book content. When you're thinking of purchasing an art book this is very useful.
MAKE Magazine: Because I just love the maker community. So many cool and fun projects going on with everything from art to technology.