get something like this, im trying to keep costs down a bit because i know nothing about cad$ and how it compares to pounds/ dollars:
a core 2 duo e6400 (and overclock if you want)
1gb ddr2 corsair value select (or wait until ram prices drop and get better ram)
gigabyte 965p-ds3 motherboard (good, cheap and overclockable motherboard)
OCZ modstream 400w odd PSU (it should do, due to budget and is a pretty reliable PSU)
gigabyte 7600gt silent pipe 2 or ati x1800gt (not sure about prices)
seagate sata 7200.10 250gb HDD
and that should be about it and it seems pretty good, if you want to upgrade to kentsfield quad core (the cheaper one that will come out next year) then all you should have to do is flash the bios and itll be quad core ready!
.. hopefully.... GL