I'm not really sure where to ask this, so I'll just post it here. I'm looking to get either a laptop or a desktop which can play most high end games perfectly. Do I really need a top of the line graphics card etc. to play these? Or will I need to fork out more?

High end games smoothly? No.
High end games smoothly with max graphics? Yes.

You don't need to drop a boatload of money to run high intensity games with reasonable fps on medium graphic settings, and building/ordering it yourself will help save a lot.

Desktop would be better suited, much easier to swap out parts. If you just want to game at 1080p on high settings you're probably going to want to look at a GTX 960 which is about 140 quid. That said though you'll probably want at least an i5 processor like the 4590 which is roughly around 130 pounds. From there it's just figuring out the best motherboard, case, PSU (probably something at least 750 watt), cooling, RAM, peripherals and operating system.

You can buy pre-built but you will be paying more, but there are some stores that will let you buy the parts and then they will build it for you. I'd recommend checking out Pick Parts, Build Your PC, Compare and Share - PCPartPicker, it lets you make PCs and will tell you if there are any conflicts. You can also look at mitigating costs by going AMD but I've never had any experience with either their CPUs or GPUs but a number of people do use them. The biggest problem is one company or another gets in bed with a game dev and they get the better drivers first.

^i can backup the GTX 960 suggestion. Ever since I got mine, its been the best purchase I ever made.

Cheers guys.

Can you point out names of games you are playing and what settings and resolution?

In any case, there doesn't need to be any guesswork about this, there are graphics card benchmarks out there that can give you a firm idea on what your frame rates are going to look like.

Take it from me, a gamer and someone who built his own PC.

My current PC is incapable of playing pretty much anything. I've since looked up specific cards etc. and have a fairly good idea of what I would need, and it's definitely not the real high end stuff.