DOOM, Halo 3, Little Big Planet, ModNation Racers, Far Cry 2, Crysis, TimeSplitters, etc.
I've bought all of them, because it makes me feel one step closer to making my own game. I've tried the C++ route, well... I've tried and given up. I've tried even using game engines like Unity and UDK, and given up.
I cannot grasp making a game when it offers stupidly high amounts of options, or coding first-hand. I like it all to be behind UI, I like having the idea for a level and just making it. Dropping in my own items or buildings. Either painting them (LBP) or just putting every scrap of detail I can (Far Cry 2/Crysis).
You're technically just using other peoples artwork and placing it to create a convinient level (except LBP where you can also create the art) which is what I love about level editors. The coding is usually simple too, LBP has switches and toggles and I can feel that it's probably a simple version of how coding works. So I feel clever when I create a cool level and my brother enjoys playing it.
What I hope for in the future is to have the UI of an editor (like Far Cry 2) with the coding/scripting part as simple as drag+drop (Crysis editor NEARLY does this but you'll still have to read SO many tutorials to create a level, it's ALMOST like an engine in the fact there is still LOTS of coding/scripting to do).
Basically what I want is, you make the level, you drop in the AI, you can give dialogue by clicking on the person you want to speak and just hit "record". You can set pre-determined animation, such as run, walk, yawn etc. The goal/mission log is as simple as dragging and dropping a "COMPLETE!" icon down onto the AI, location, item, whatever it may be and the goal/mission would be complete.
I'd also love it if they could make a simple MudBox/zBrush style asset creator. You toggle values such as head, body, feet, hands, etc. Then you add detail with brushes. It'd be sweet if these models could then be shared online, because we'd see some truly unique art styles. No longer would the editor determine WHICH models you place in the game.
The thing is if they made software like this they could charge anything they want. They'd effectively have a simplified game engine. It'd be UI-only and because of that ANYONE could make a game, so is this the reason they haven't done this?
In terms of other editors be on the lookout for QuestMania and ShootMania (the editor IS the game here so could it be as robust as something I've described?!). Also, StarCraft II. Which is looking to give LBP2 a run for it's money.