New PC Spec

It's been a LONG time but my Athlon XP 3000 system is not cutting the
mustard anymore..

My requirements are a bit weird :

I want a desktop machine for general surfing about (so has to be quiet)
Also due to work I'm often loading up to 2-3 VMs (one of which may have
an Oracle database inside - sigh)
I do some development, a touch of video-encoding (but not so much now
I can stream mkv to TV), etc.
No great Graphical demands. No games, but I may download the odd demo
now and then.
OS will be some 64bit flavour of Linux. but VMs will be RHEa/WhiteBox
L or Windows 2003 Server.

My current system has served me well, but I want to start making more
use of VMs rather than hooking up slow laptops when I want to install
some 'enterprisey' software to play with..

Budget (~£500/US$1000)
So..
My initial stab was :

CPU(£120) Intel Core Duo E82400 or Quad 6600

MOBO(£100) IP45 Chipset for 16G Max :
Eg. Gigabyte GA-EP45-DS3P iP45 Socket 775
http://www.ebuyer.com/product/146846
(although an eSATA would be nice for backups)
Can eSata be added afterwards via PCI-E?

RAM(£110) 8GB 2 * (4G Kit) CCD2 PC2-6400/DDR2-800
http://tinyurl.com/6nmdnr

GPU(£20) Any cheap fanless dual head. My TFT are currently VGA
I may upgrade this later (H.264 hardware support maybe)
but its not an immediate priority.

Thats about £350.
The rest will be
£50 HD 500GB SATA
£75 Case with PSU (eg Antec http://www.ebuyer.com/product/128045
£10 DVD burner (http://tinyurl.com/5tpjlv)

Cables etc.

Comments?
My biggest Q is whether to go Quad or Duo.
A lot of the benchmarks seem to be single app tests, rather than
testing an OS doing a few different things...
However I'm not speccing a production server, these VMs may be loaded
up for a few days testing/hacking and then torn down again,
so should I really concentrate on Quad that much??

Any pointers appreciated..

Lordy