so I take it you want things nice and quiet.
I wouldn't bother with any "silent" coolers zalman offer
tbh, they'll either be quiet and cook your cpu or noisey in my experience.
Xigmatec's tower coolers are very good coolers and with something like a noctua fan will be extremely quiet.
Wouldn't bother with DDR3 with anything less than X58 and core i7 cpu's (expensive). Persoanlly I wouldn't even bother with intel, AMD offer fantastic solutions for both strong integrated graphics (I take it you aren't gaming) and pretty damn good Quad cores.
So in light of that,
AMD phenom II 940 BE ~£195 + Sythe ninja II or Xigmatec (as above) ~£30
Asus 780G -EM mobo ~£60
4GB crucial ballistix DDR2 ~£40
Antec P180 mini ~£60 (uATX which the board would be too)
640GB WD AAKS ~£55
LG HD/Blu ray ~£60 (or just standar SATA optical £15)
450W Corsair VX ~£65
I would get an fan cooled PSU. THe corsair's are super quiet as are enermax modu and pro series.
On board graphics are strong enough for blu ray and light gaming but you could always add a passive card later.
If you wanted it completly silent then you could change the antec tri cool fans for noctua and it really would be.