I'm not too fond of XKCD, but Homestuck is the most entertaining and interesting of webcomics that I've read. When Andrew Hussie described it as a combination of EarthBound, SPORE, and the Sims, that was a pretty accurate representation of the comic's complex story. It's also interesting when you take into account that Hussie makes his living off of MSPA, and so many different aspects of Homestuck and Sweet Bro and Hella Jeff have saturated the Internet and developed into established and well-known memes.
