We've done a ton of DIY renos, and I'd agree that Home Depot has better selection than Rona. We find that Rona is fine for tools, screws, wire, etc, but for fixtures, flooring, paint, Home Depot tends to carry better quality products.
Although if you are thinking of having Home Depot install something (like flooring or cabinets) I'd check around with specialty stores first. Often the final installed price on those things ends up being more expensive through HD. If you're doing it yourself then it's not an issue.
For paint we love Benjamin Moore - great colour selection and quality paint, although more expensive than the brands at the hardware stores.
