Gloves from Home Depot or whatever ("Watson gloves" are pretty good, I have some thin-ish biking/yardwork gloves from them, bought for $12 and use from everything from biking, yardwork, camping and airsoft). Boots, any outdoor store will carry them however for military boots it'll be a premium that you're going to pay.
Personally I have a pair of hiking boots bought from Coast Mountain Sports/Sport Chek, got them $100+tax on sale, they were like $150 retail (clearance sale).
However once these wear out (on it's last legs however may last one more season, I've had them for about 5 1/2 years now) I'm planning on buying a pair of nice military boots. I've been looking around at things like 5.11 and those "Adidas Tac boots" and such so if you find any good deals shoot me a PM. Looking for quality at a good price so if they're $300 quality boots (not just buying for namebrand) for $250 or something I'll jump for that. I'll be using them for more than airsoft so quality is paramount.
Goggles, JT Pro Flex or Spectra I believe works well. I know there is one model that you can remove bits and pieces (ie. somewhat modular) and can remove the goggle part entirely to wear just that but the name escapes me...
Otherwise there's also the "Save Phace" masks which are super low profile but doesn't meet the requirements of a removable goggle part.
Pants.... Why go to the person who sells them of course
(Army Issue, Port Credit, bit of a drive but not as bad as to Toronto at least)
EDIT: Also if you're not afraid from ordering online tehmedic suggested a great site. I personally have dealt with airsoftpark.com and I must say for a drop shipper excellent service and much more than what you'd expect from a retailer who dropships products. Reply given to me I think in like 48 or 72 hours (I guess you can give them 1 day off because it's Sunday, so I guess like 1-2 business days to reply to messages about questions about the product).