I need some LEDs to fix with my canopy. The length of the aquarium is of 125cm. I do not wish to use tubes due to power consumption and moreover I am not planning to have delicate fish but rather something like guppies, neons etc
Are you planning on live plants? The high-power Cree LEDs are supposed to be pretty good for live plants and corals when you've got enough of them. If you're only keeping fish, there are cheaper, low-power LED options.
You'd be best off with a few of the Cree LEDs over a mass of cheap LEDs if you want some plants. This is especially true if your tank has any depth to it. Can you give us the dimensions? It'll help with lighting recommendations.
That's an interesting tank. It's definitely deep enough to need the high power LEDs. For low-light plants, figure that you'll need one watt of light per gallon. You might be able to get away with less light. Your tank is approximately 50g. You'd need 15-18 3W LEDs or 40-50 1W LEDs to adequately light your tank.