We love the previously mentioned Read It Later Firefox extension, which offers a simple method for saving bookmarks to read later. The I Need to Read This bookmarklet offers similar functionality without the extension dependence.
As opposed to the Read It Later extension, the I Need to Read This bookmarklet is browser agnostic (no Firefox requirement), and it doesn't require yet another add-on to bloat up your Firefox install. You actually get two bookmarklets with I Need to Read This. The first is the titular bookmarklet ("I Need to Read This"); the second, labelled Read an Article, fetches and loads one of your bookmarks. Simple, lightweight, and effective.
Of course, you do miss out on some features if you opt for I Need to Read This over Read It Later—including offline reading and awesome bar integration—so it's up to you to decide which better fits your needs. Either way you go, both tools offer a great solution for bookmarking and cycling through to-read items. If you prefer I Need to Read This but wish you could access it via an extension, an expirimental I Need to Read This extension is in the works.