Cash is king. Well, apart from online purchasing.
If someone were to look at my bank statements for outgoing monies then almost all they'd see is PayPal transactions, which without access to my eBay & PayPal accounts is practically meaningless in terms of what was bought.
For buying things in bricks'n'mortar shops I almost always use cash, mainly because it helps me keep track of what I've spent as I can instantly see how much I have left in my wallet, and with cash it means if you don't have it you can't spend it and get into debt.
If I were to use cards all the time it makes it trickier to keep track of what's spent because my online bank statement isn't as realtime as the cash in my wallet, and at the end of the day I prefer physical cash in my hands whereas banks it's all just numbers on a screen.
For really big purchases a credit card is very useful though, mainly for the protection it gives compared to a cash purchase.