With Overdrive's new 'read in browser' option, it opens up a whole new slew of options.
Not all books can be read in browser, but the ones that can look very nice, especially if you're using either the Firefox add-on (if you're reading in IE) or through one of the other approved browsers (Chrome, Opera, Firefox etc).
If you have a tablet, I suggest this: read any books you can in browser. Save them in your favorites so you can read them off-line. If you have a book you can't read in browser, then download it into the media console.
My reasoning is this: it's one less step. By reading them in browser, you're saving yourself the time of downloading them. While it can be a few minutes for some books, depending on the internet connection, it can take fifteen, twenty minutes or longer for other books. By reading them in browser, you don't have to download them so you can start reading them immediately.
It saves your place, you can place bookmarks and a whole slew of other cool things.
Save the media console for when you can't read them in browser, or for those audio books.