The one thing that is very important to me, and I imagine other users from what I've seen here is the ability to group my books into categories (non-fiction, fiction, fantasy, suspense etc) on the device.
Preferably these would be custom categories that could be created like on the Kindle where you just click "add to category" and an option comes up for you to name a new category. Since the Kobo Touch already has a "Favourites" organizing method I'm hoping it wouldn't be too farfetched to add the ability to create further groups.
Especially for people who would like to browse through their larger collections (rather then search for a specific title or author) this would be an excellent feature to have. If you're reading this Kobo, please keep up the firmware updates and make this good ereader an excellent one!