Instapaper and the Kindle make a good combination.
You can set up Instapaper to assemble a digest periodically from stories that you have identified as interesting. It will email that digest to Amazon’s free conversion service, Amazon will convert the file into a Kindle-friendly format, and the file will download via WiFi when it is ready.
I have it set to produce a daily digest, but the appropriate setting probably varies depending on how often you have time to read interesting but non-essential material.
One Instapaper tip: Always use the ‘Instapaper Text’ browser button before the ‘Read Later’ browser button. When I click the ‘Read Later’ button directly on websites, Firefox often crashes completely. When I click ‘Instapaper Text’ first, then ‘Read Later’, it almost never crashes.