For years my default rehydration drink has been flat coke and water, my default recovery drink, black coffee. But because I've been riding harder, I've changed my mind: energy drinks really do take that half empty post-ride ache out of your legs.
Squeezy's energy powder is a fairly standard mix, with maize starch, fructose and glucose delivering 45g of carbohydrate from a 750ml bottle. There's a bit of vitamin B1 and also a pinch of sodium, which gives better rehydration, but no yucky artificial sweeteners. It sits okay on the stomach - just the odd burp. It's meant to be used before, during and after riding. I've not found any benefit from drinking it during admittedly short-ish events, but it definitely helps to down a whole bottle afterwards. (The more carbo-rich Squeezy Carbo Load Powder ought to be better still.) Some cyclists will prefer a drink with protein post-ride, but as most contain whey and I hate milk, I'm not one of them. This tastes nice, does the job as well as any other energy powder I've tried, and is comparably priced. It's great when you've got a hangover, too. It's also available in 49g sachets for 99p - less hassle but more expensive than a tub.