Okay, a couple years ago I picked up an Asus N53S for myself, and my sons each got Acers (I don't remember the models on theirs). My Asus is still kicking and doing a pretty good job for what I want it to do.
The Acers, however, have taken a beating. Mostly because the boys are always on them, either for school, the Internet or for playing.
So, I'm thinking new laptops for them. However, I don't want to go ape-shit because the eldest is finishing up his sophomore year and it's likely when he goes to college he'll either need another upgrade or get specific instructions about the type of machine he'll need.
In other words, I need another two year machine.
Country where it will be purchased: USA
Maximum budget: $600
Max size (can be in screen inches, dimensions, weight): They have 15.6 displays now, so I'd like to keep it there.
Planned usage (what kind of games or specific games it must run, if heavily gaming at all). Ideally you'll point out what resolution and settings are your standard, based off of what I've laid out in the OP:
The Acer is 720p and runs Diablo 3 pretty well. I'd say Intel Quad Core with an nVidia would be the choice here. I'm going to doubt that I can get them into 1080p at the budget above. We have consoles for many of the games they want to play, but they really want to enjoy things like D3, Minecraft and other Steam games they pick up on sale (so not necessarily the latest/greatest) at medium to medium-high settings without suffering lag.
Whatever else you find relevant, misc. things such as desired battery life, screen resolution, fan noise, etc.