I'm not a fast reader myself, either. Probably faster than the average joe, but slower than most "bookies." I remember in my school days, I looked into speed reading so I could get through my assigned reading faster. One of the techniques I remember reading about is to split the page up into sections and try reading those sections at a time rather than focusing on each word. Basically, they recommended drawing vertical lines down the page to break it into thirds or one line down the middle to break it into halves. It helps with not pronouncing words in your head, like others were suggesting. I actually drew lines onto my pages (I'm sure my English teachers weren't amused)...it'd actually work well on an ereader if you found a non-permanent solution. Dry erase marker, maybe? (I don't want to be the first to test it though!)
I know you said you don't want to speed read, and neither do I, exactly. But like Solicitous said, now I have such easy access to all the books I want to read, I want to get through each one so I can dive into the next! It doesn't help that I seem to be attracted to sprawling, epic series.