I would go for something like this:
BenQ FP202W 20" Widescreen LCD Monitor - Black
(£152.74 inc VAT)
Western Digital Caviar SE16 250GB 2500KS SATA-II 16MB Cache - OEM
(£46.99 inc VAT)
Sapphire ATI Radeon X1950 Pro 256MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail
(£105.74 inc VAT)
GeIL 2GB (2x1GB) PC6400C4 800MHz Ultra Low Latency DDR2 Dual Channel Kit (GX22GB6400UDC)
(£111.61 inc VAT)
Asus P5N-E SLi nForce 650 (Socket 775) PCI-Express DDR2 Motherboard
(£82.24 inc VAT)
Intel Core 2 Duo E4300 "LGA775 Allendale" 1.80GHz (800FSB) - Retail
(£109.26 inc VAT)
Liteon DVD-8900 16x DVD±RW/RAM (Black) - OEM
(£16.44 inc VAT)
Akasa AK-ZEN-01-BK Zen Black Case - No PSU
(£29.36 inc VAT)
Seasonic S12 430W Silent ATX2.0 Power Supply
(£46.99 inc VAT)
Total : £703.99 (Shipping not included)
If you can wait a few more days the price of the e4300 is likely to fall so you'll be within your £700 budget
BenQ FP202W 20" Widescreen LCD Monitor - Black
(£152.74 inc VAT)
Western Digital Caviar SE16 250GB 2500KS SATA-II 16MB Cache - OEM
(£46.99 inc VAT)
Sapphire ATI Radeon X1950 Pro 256MB GDDR3 HDTV/Dual DVI (PCI-Express) - Retail
(£105.74 inc VAT)
GeIL 2GB (2x1GB) PC6400C4 800MHz Ultra Low Latency DDR2 Dual Channel Kit (GX22GB6400UDC)
(£111.61 inc VAT)
Asus P5N-E SLi nForce 650 (Socket 775) PCI-Express DDR2 Motherboard
(£82.24 inc VAT)
Intel Core 2 Duo E4300 "LGA775 Allendale" 1.80GHz (800FSB) - Retail
(£109.26 inc VAT)
Liteon DVD-8900 16x DVD±RW/RAM (Black) - OEM
(£16.44 inc VAT)
Akasa AK-ZEN-01-BK Zen Black Case - No PSU
(£29.36 inc VAT)
Seasonic S12 430W Silent ATX2.0 Power Supply
(£46.99 inc VAT)
Total : £703.99 (Shipping not included)
If you can wait a few more days the price of the e4300 is likely to fall so you'll be within your £700 budget
