Building a new computer. Help needed

Hello There  

So it's that time I need a new computer. My current PC is ok i suppose, but i'm the type that likes to be able to run everything in the PC gaming industry that's currently out.

Current PC:
Intel Quad-Core @ 2.4ghz
4 GB Ram ddr2 speed (yeah i know it's slow)
ATI Radeon HD 5770 1Gb GPU

I'm wanting to build a new pc with the Intel i5 processor with around 4gb DDR3 1333 Speed ram and a graphic card that is much faster than my current. I have everything else monitor, speakers etc etc already. It's mainly these 3 parts i want to upgrade and get a new case+PSU. I'm planning on selling my old pc(without HDD) to a friend. Also I have a windows 7 64bit OEM disk that i bought before, so i don't need windows either.

I'm thinking of getting one of these 2 Barebones bundles here from novatech:
Intel i5: http://www.novatech.co.uk/products/barebones/bb-34504b....
or a cheaper bundle: http://www.novatech.co.uk/products/barebones/bb-61004b....

The problem here is that the Intel bundle has a rubbish PSU that i'll have replace for a decent graphic card to work. I'm not sure if the AMD chipset bundle is as great as the i5. I'll be willing to pay the extra if the i5 chipset bundle is much better.

Now the graphics card. I'm looking for a graphics card I can buy between £100 and £150 (maybe more if it's really worth it) But i have no idea. I got the HD5770 before because at the time it was really good value for money at the time. Up to now that has worked well. I haven't tried a Nvidia Card before so I don't know if they are better and whatnot. I play games in 1440x900 Resolution if that helps. (read somewhere that ATI are better for higher resolutions or something.)

I'm not a master techie, but I do know the basics of fitting HDD, GPU etc. Just fitting a MOBO to the case might be problematic. But if it's worth it i'll do my research. If there's some other good deals some of you might now of.

The games I mainly play are WoW, League of Legends, GW2(For when it's out), dota2 and varius other games sometimes. BF3, Deadspace2.

Any help at all is much appreciated.
Thanks, Dave

Side note: I live in the UK