well i built my system for £800.00 with a 19" LCD take a look at my sig.
i'd keep that sound card and dump everything else if i were you
get yourself a good AM2 mobo (think of your upgrade path) and wait for the DX10 cards to come out, you should be able to pick up a great dx9 card for much less (they are already dropping rapidly in price) take a look at the 7950GT
oh and take a look at the 3500+ its a great little chip for next to nothing, overclocks well (got mine to 2.6 ghz on stock yesterday). games that you play dont use a dual core and games probably wont for a while, and if you do need an X2 you can always pop one in later