Ok now to answer your question.
1)Your Going for a Asus/Msi/Dell Build
*Website Links*
www.dell.com (Dell)
www.newegg.com (Msi)
www.Asus.com (For The Asus)
These MIGHT not work if you live outside the US/Australia.
So..
www.oo.com (Ships to UK/Europe)
www.newegg.com (sometimes Ships to World-Wide)
www.ebay.com (Sometimes ships to World-Wide)
O
verclocking can be done on ALL of the Asus/Msi/Dell Desktops.
Moniters come with them
and they are mostly under $900.00 (Depends where you live again)
UK=$300-400.00
USA=$400-500.00
Europe=$550-600.00
It all Dpends on where you Live.
Also MOST of them will have Good graphics cards and Good Moniters Sizes
ASUS (RECOMMENDED BY ME)
EDIT:i just sore your Comment ok your going to want to go with
www.newegg.com (That WILL save alot of money)