Lo all, been a while

I have finally decided that my rig needs replacing (its a P4 ). Spent most of today looking at possible new setups and am more confused than when I started.

I have a monitor already (1280*1024) and a budget of £700. I have never built myself a PC before and am a little worried that I might screw it up. I will not be overclocking anything.

Anyway I came up with

I wouldn't be buying it til early January so prices should come down and stuff so this is in no way a final build, however I have quite a few questions.

Would this all be compatible?
Does the CPU come with heatsink and fan attached or do I have to faff around with thermal paste and add my own?
Is a 650W PSU enough if I plan to add another 4GB ram later on and upgrade to a DX11 card?
Is a rig like this going to last me 2+ years (including new GFX card and RAM)?
Is scan.co.uk a decent place to purchase parts from and what are they like about DOA items?

That's all I can think of atm in this inebriated state, I'm sure I will come up with more. Any and all comments/help is appreciated .