Depends a great deal on what you want to get from it, I built my own system from scratch early this year, knew I didn't want to play the most demanding games etc but wanted a fairly fast machine went to PCW and talked to an assistant who seemed to know what he was talking about and ended up buying a ASUS TUSL2-C mobo and a intel celeron 1g processor with a 34mb graphics card and memory and 40gb h/d, new tower case and cd-rw all for about £300 all from the "brown box" range, already had the keyboard/mouse/monitor etc so saved a few quid. No probs putting together and a great sense of satisfaction at the end!! Without the advice of the guy at PCW it might have been different!.
(god sounding like gandolf now)!!!
Min I would go for is 40 gb h/d (£50ish) cd-rw (£30ish)dvd drive (£35ish) as much memory as you can stuff in and either 32md graphics (£35ish) or 64mb modem £10 mobo/processor to your choice! case worked out @ £25
I know that alot of people will disagree and say what a dinosaur etc! but it suits me, run win me networked on broadband and no probs so far!!!!