Try NCIX for a good, reputable Canadian PC parts supplier (they have a storefront in Burnaby BC I think)
from your list above
http://www.ncix.com/products/index.p...ture=MicroStar $107
AMD 64 3700
http://www.ncix.com/products/index.p...ufacture=A MD $312
video card
http://www.ncix.com/products/index.p...INTERNATI ONA $65
However I wouldn't get this video card for any gaming (especially with such a good processor)
go with at least an x800GT or 6600 series card (I got a 7800GT for my recent system)
6600GT video card
http://www.ncix.com/products/index.p...nufacture=eVGA $175
memory
http://www.ncix.com/products/index.p...ture=COR SAIR $115
hard drive
http://www.ncix.com/products/index.p...ture=Se agate $135
Windows XP home
http://www.ncix.com/products/index.p...ture=Microsoft $112
DVD burner
http://www.ncix.com/products/index.p...nufacture=BENQ $57
do you have a case? you'll probably need a new one
all prices are $Canadian and regular prices - they usually announce a new sale every Thursday morning and you can often save 5-20% on some components.
Be careful about ordering from the US - shipping companies will charge a large fee for brokerage through Canada Customs (as well as havein to pay GST and any import duties).
b

I didn't show it in my post because theres not much you can really do to go wrong with a HD, well at least the one you picked! 
