Out of curiousity.
Does the lad have a pc currently?
What resolution is the monitor?
What games are you expecting him to play?
School work?
It's a bit of a false economy building the best rig you can for stuff it may not be doing for a couple of years when in a couple of years better kit will cost less.
Such as a GPU that will comfortably max out settings at 1440 with the latest game titles, if your lad is too young for the games people have in mind and using a 1080p or less monitor.
Specifying monitor resolution and connections, even keyboard/mouse connections can also be worthwhile. Someone I know has onlly VGA and PS2 connections which limits choices.
One of the best things to add though would be an SSD, even my lads, who share a PC, have a small 120gb SSD for the operating system, it does not take long to direct folders to an HDD.
Another thing I consider more is the case. My lads somehow managed to get a lot of dust in their old PC's, now they have had a couple of cheap cases when really young, currently a Silverstone TJ08B is doing great, the dust filter works a charm, and it's small and unobtrusive.
But they have no use for optic bays, having broken an optic drive previous, and now that my lad is in high school I think he would like something nicer than a boring black box.
I had an NZXT project, white S340 with remote RGB lighting, and I think the kids want that so now I am considering a bit of component juggling here, I do not want my kids playing the game titles that demand expensive GPU's and CPU's. Quite simply I do not agree with my 9yr old and 11yr old playing GTA 5 and such titles with age restrictions. Though they manage to get similar older titles at times on their Xbox and they repeatedly tell me their mates have this and that.
As such I am sure an old Q9550 or G3258 or such, with an old 7950 or 750ti would be all that is needed for their 32" 1080p display.
Though they would probably prefer an Xbox one.
