Looking to get a new PC and need some advice

So at last I'm going to do what I've been wanting to do for over a year now. My current laptop is now 3.5 years old and it's near impossible to do any normal tasks without trouble, let alone play any remotely new games even on the lowest settings. Guild Wars 2, which I'm playing right now with like 5-15FPS under best conditions and lowest settings, only uses DirectX 9 to run on a wider variety of systems and even that isn't enough for my laptop (a friend told me that's mostly because of my shared-memory GPU). I doubt it would take much to run it on highest settings but I'd still like to have the option to play new PC games at decent settings and smooth framerate.

My budget is about €1000, although I don't want to spend quite that much. A mid-to-high range PC that can last me at least 2-3 years would be what I'm most looking for, a beast of a PC is nothing I'd really take advantage of and I could use the money for other things. Since I've been using a laptop, I need a monitor too. Again, nothing fancy and expensive. My laptop has a 17 inches screen so something a bit bigger than that with a resolution of 1920x1080 instead of my current 1400x900 would be enough.

Then there's also the question of building or buying...would building one save me enough to be worth the trouble and is it easy enough to do?

I know there are some PC enthusiasts here on C3 and since I'm no expert when it comes to these things, any help from you guys would be greatly appreciated!

I'm not really into technical specifications and such when it comes to computers. So I can't help much there, but this video was great on Tested. They built a new future-proof PC for Jeff and it basically shows you how to build it all.

It's very interesting and enjoyable to watch too, I found. I ended up watching it all.

Im actually selling my PC, its got a pretty decent spec, if your interested let me know?