You'd be really dissappointed if someone said it rubbish considering you just bought it now wouldn't you?
Seriously its ok, only thing I don't much like the look of is the graphics, a 7100GS is fairly low, if you're not a gamer then fine but even for a sub £500 PC most come with a 7600GS which is a better card. Have a look at the magazine for comparisons. Hard drive size ok considering the price and the monitors ok but some do a 19" at the price but yours is widescreen so thats not bad, 1 gig memory ok. And you picked XP instead of Vista but personally I would probably have gone for XP Home as its slightly cheaper and most people don't need the extras you get in XP Pro.
Its an OK PC for the money, if you do upgrade the graphics later you will need to renew the power supply as 400 watts can't handle the newer cards but as long as you are happy. Its not a bargain but its a reasonable buy and you didn't get ripped off if thats what you wanted to know.