Best rig for Gaming/Future proofing?? Choice inside......

[enzed]

O.K so I have a choice of two rigs but am unsure which way to go, as it stands I do a lot of gaming, movies, poker, music not so much major apps like photoshop etc.
I am wondering whether to go Quad core now or go Dual Core for greater speed and upgrade to a Quad Core chip later, anyway two choices are below...

SPECIFICATIONS
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- Intel Core 2 Quad Q6600 2.4GHz 8MB L2 Cache Quad-Core Processor
- Transcend 4GB DDR2 800MHz Dual-Channel Memory
- Asus P5K/E WiFi Intel P35/ICH9 Chipset Motherboard
- Asus nVIDIA GeFORCE 8800GTS 640MB DDR3 PCI-E Display Adaptor(Factory OCed)
- Seagate or Western Digital 500GB 16MB Cache SATA2 Hard Disk Drive
- Asus QuieTrack SATA LightScribe Dual Layer DVDRW Drive
- iCute S901-5G ATX Mid Tower Chassis
- Thermaltake Toughpower 750W Power Supply Unit
- Front Audio Connectors (mic/headphones)
- 1 x 25cm / 1 x 8cm System Coolers
- 2 Front / 4 Rear USB 2.0 Connectors
- HDTV, SPDIF out & eSATA Connectivity

or.....

SPECIFICATIONS
*************
- Intel Core 2 Duo E6850 3.0GHz 4MB L2 Dual-Core Processor
- Transcend 2GB DDR2 800MHz Dual-Channel Memory
- Asus P5N32-E SLI Plus nVIDIA Dual X16 SLI Chipset Motherboard
- XFX nVIDIA GeForce 8800GTS 320MB XXX PCI-E Display Adaptor x 2 in SLI Mode
- Western Digital 400GB 16MB Cache SATA2 Hard Disk Drive
- Asus QuieTrack SATA LightScribe Dual-Layer DVDRW Drive
- 8 Channel High Definition Audio
- Gigabit High Speed Ethernet
- iCute S901-5G ATX Mid Tower Chassis
- Thermaltake Toughpower 750W Modularised Cable Management PSU
- Front Audio Connectors (mic/headphones)
- 4 Front / 4 Rear USB 2.0 Connectors
- 1 x 25cm / 1 x 8cm System Coolers
- 1394a / eSATA Connectivity

either system will be running 64bit Vista Home premium.
Anyway any thoughts are more than welcome, thanks.