I think what i recomended is good enough for your needs. You said for gaming so you might want to get 2 gigs ram in dual channel and your right Gaming doesnt depend much on the processor. Im guessing you have a gfx card.
Hey my Mum was born in Winnipeg. You guys already got winter I hear...
Okay, the memory is a big expense for you - you can get whatever CPU + mobo, but memory is expensive! So in Canadian $$ we can spec a nice quality gamer platform for you for $550:
Intel Core2 E6300 CPU - $215.
ABit/Asus/Gigabyte P965 mobo - $175.
2 x 512MB OCZ PC2-5400 (SpecialOps) - $160.
This is good-quality stuff, take your pick of mobo mfg. because cost is similar.
In a perfect world you would invest in 2 x 1024MB but that will blow your budget right out of the water.
Here is a good Canadian link for you, so you can check sharp Cdn pricing (or I guess they will mail-order too): http://www.pccanada.com
But trust me, support your local computer shop if you are able - one day you're certain to be glad you did.
Seriously, they're the same board (even Gigabyte admits it), except that the DS3 has solid-state capacitors. This will prolong the lifespan of the board. However, the S3 will last longer than the lifetime of your system anyways, so if you plan on keeping your rig longer than 5 years, get the DS3. They overclock THE SAME. Otherwise, just go for the S3 and save the extra money. Put that money, along with saving the PST into getting more/better RAM Get 800 if possible within budget. If not, get some decent 667 RAM, don't get the Value Series crap. Get some Corsair, OCZ, G.Skill, Super Talent or the like....whatever you can afford, probably just 1 gig. Depends if you have a preference, but entirely on your budget.
Here are some options, best bang-for-buck for the good stuff here in Canada: