Thinking about an upgrade

Hey all,

I last upgraded my system in 2003, and I feel it's time for an upgrade! Currently i'm chugging along (surprisingly well) on :

AthlonXP 3000+
A7N8X Deluxe Mobo
1.5gb ram
XFX 7800GS Extreme Edition GFX Card
Xtreme Gamer Sound Card (this can stay I think)

Was looking for a system that can run modern games well, and run well with all my photography and art software. I'm looking to spend around 450 pounds tops (around 650$). Would this be enough for a modern upgrade?

How ya doing, buddy?

I'm getting a lot of people advising me to go for the Intel and Ati, rather that AMD and Nvidia. If I do go with their advice, how does this sound -

Intel Core 2 Quad Q6600 G0 Stepping (2.4GHz 1066MHz) Socket 775 L2 8MB Cache (2x4MB (4MB per core pair) Retail Boxed Processor - Ebuyer
Gigabyte GA-G31M-S2L iG31 Socket 775 Onboard VGA 6 channel audio mATX Motherboard - Ebuyer
PowerColor HD 4870 1GB GDDR5 Dual DVI HDTV Out PCI-E Graphics Card - Ebuyer
OCZ 4GB (2x2GB) DDR2 800Mhz/PC2-6400 Memory GOLD DUAL CHANNEL Unbuffered CL5(5-5-5-18) - Ebuyer

I'm still debating whether to fork out the extra 100 for the 4870 or go with the 4850. At the moment I play on a simple 17" LCD screen, not widescreen or anything. I might upgrade this later on though.

Additional Spam:
Also, would a few months old Arctic Power 600W PSU support all this?

There's nowhere I can't reach.

It's a toughy for sure! I'd like to play some of the recent games, Assassin's Creed, Crysis, Far Cry 2 etc on high graphics, something i've never had the opportunity to do before now. Just not sure if I should go for the 4870!

This thing is sticky, and I don't like it. I don't appreciate it.