Instapaper - saves web pages in text for offline reading
The BBC News - could definitely use some improvements, but downloading all the articles in the morning when I'm hooked into power saves battery life later. I can also read the articles anywhere I don't have access to the net.
Wikipedia - most of the wikipedia articles wthout pics right on my iPhone. App would be even better with added features. It's pretty basic, but offline access to wikipedia articles is great for loading time, battery life, and also when I don't have access to the net.
Wikipanion - I can download any article missing from the Wikipedia app and access that article offline, and it's great for viewing articles better viewed along with the pics.