You need to have proof that you have the minimum required funds available to you, but you do not have to have it on you in form of cash/cheque. It is rare that the officer even asks for this. They will ask you how much money you physically have on you, and how much you have "available" to you.
Personally it's up to you how much you carry on you. You can take as much as you want, but you have to tell them. Personally I had about 200$ cash on me and then had the rest in my bank account I could access from Canada.