Yeah, it really is a challenge.
Back then, when I only had a couple of titles on a single console, I could simply take a break from my current run of a title and devote some time to the other titles so I could essentially finish them all around the same time.
Now, with 3 consoles and 3 handhelds and a dozen titles (which consist of sandbox action titles and RPGs), it seems like it could be a little tricky without buying new titles (which I still aim to do).
However, there are different ways to actually tackle your backlog without it feeling like a chore.
The first is to put your games in an order that you are comfortable in completing. You could choose to play the titles you are most interested first and move down the list. You could also choose to play one game per genre and not touch another until you've finished it. That way, you don't end up playing 3 RPGs at once, having your attention and interest dwindle over time. Concentration on a single system is also a good idea, as you can tackle titles that are usually not as time consuming as others found on different systems (handheld < console < PC).
For example, my current list of titles to tackle includes Donkey Kong and Shantae for the 3DS (virtual console), Crono Trigger for the DS, Persona 3 Portable for the PSP, Assassin's Creed 3 for the PS3, Odin Sphere for the PS2, and The Last Story for the Wii.
I will be focusing on completing Assassin's Creed 3 first (even though I don't want to), playing The Last Story every other day (as I need to familiarize myself with it again), and complete both Donkey Kong and Shantae as I'm close to doing so and do not take a lot of time to progress.
Once these titles are done, I can finish Persona 3 Portable, Crono Trigger, and Odin Sphere before moving on to other titles.