Rip_Uk

I am looking to build a Windows 7 quick multi tasking computer base system that will not be used for heavy gaming although an up to date graphics card would be ideal for a good price.

What I have already:

The Windows 7 software (on order)
An Antec Three Hundred case with cae fans
Monitor, Keyboard and mouse
An Audigy 2 ZS sound card

What I need

A motherboard
A quick processor capable of handling multiple applications
4GB RAM
Around a 1TB SATA hard drive
A decent PCI-E graphics card
A DVD R/W DL optical drive
A power supply capable of handling the components

I have £400-£500, possibly more if needed and need to buy in the UK.

Does anyone have any ideas on what I should be looking at?

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Antec Three Hundred
Samsung SM226BW 22" TFT
Msi P55 CD53
Intel Core i5 750
XFX HD 4870
4GB Corsair Dominator DDR3 PC3-12800 (8-8-8-24)
Samsung Ecogreen F2 1.5TB HDD
Samsung SH-S223 22x DVD±RW/RAM/DL
Corsair 650W TX
Logitech G15 Keyboard and G5 mouse