For 600$ CDN you could easily get an i5 and 16GB of ram on a mid-range motherboard.
Would you be interested in overclocking?
EDIT: It would also matter if you needed to buy a new copy of Windows.
Here's a quick i5-4690k combo, though this would be tight
PCPartPicker part list:
http://ca.pcpartpicker.com/p/8RKtsYPrice breakdown by merchant:
http://ca.pcpartpicker.com/p/8RKtsY/by_merchant/CPU: Intel Core i5-4690K 3.5GHz Quad-Core Processor ($299.99 @ Memory Express)
Motherboard: MSI Z97-G43 ATX LGA1150 Motherboard ($124.99 @ Memory Express)
Memory: G.Skill Ripjaws X Series 16GB (2 x 8GB) DDR3-1866 Memory ($157.99 @ Memory Express)
Total: $582.97
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2015-01-26 10:20 EST-0500
For 582$ at Memory Express - I don't have an issue with MSI boards, though I know a few people who won't touch them, so that's a consideration.
You could very easily save money by:
a) Getting a non-overclockable i5. They start around 215$, where the K is 299$
b) Going with 8GB of RAM instead of 16 would save you ~70-80$
c) Getting a non-overclocking (non-Z97) motherboard which would save you 25-50 depending on featureset. I would only make this change if you don't get the i5-K
EDIT2: Bear in mind I haven't done any price matching - you may be able to save some money by doing that. I went strictly based on what MemExpress' prices were.