If you're buying online then go use shopbot.ca to find the lowest selling price of each component, cut/paste the link into notepad or word and then go buy your system at ncix.com and use their pricematch feature.
Or find a local place that will also match prices and use shopbot again.
[edit] ballistix RAM 2gb is on sale right now for $100 at tigerdirect.ca, buy, buy, buy![/edit]
good luck!