I use GB lists for both. It's far from elegant and could be a whole lot better, but its the best I have found so far. Sadly the site redesign made "Wishlist" super god dam hard to add games to by removing the add to list option on games pages. I really hope they get that stuff working again. This is my current Wishlist. It's hard to keep track of games these days because there's just so dam many coming out. It's even harder when half the games are small indie stuff that never get added to the site and I'm always too lazy to do it myself.
Any who, I just use my Collecting Dust: Back Log list for my console stuff. I have so many dam PC games on Steam that it would need its own list and is a separate beast all to itself. I hate having such a huge backlog too. Every time I buy a new game I feel dirty for buying it when I'm literally looking at a shelf full of over a hundred games that have never been open and and hundreds more a few mouse clicks away on my PC.