After spending some time investigating cryptocurrencies, I decided the best for me is to mine Gridcoin (GRC). I have a low cost gaming laptop, I mostly wanted a good CPU and enough RAM but I also got 2 GPU units (Intel and Nvidia). As I am not a gamer, I decided to find a use for this sleeping Nvidia card.
But first, let's have a look at Bitcoin. Mining Bitcoin means solving "arbitrary" SHA-256 cryptographic hashes, which results in correlating the currency with electricity consumption (when using the proper equipment: Bitcoin ASIC).
On the opposite, mining Gridcoin does not require any specific hardware, the CPU and GPU of a normal computer will do and it helps the scientific community by providing them computing power. Crunching to search for new prime numbers, new amicable pairs of numbers, or even for pulsars in the universe is quite exciting and the potential outcome of such projects has a higher value than pure electricity consumption. It makes more sense to me.
You can find a list of the projects here and start mining installing the BOINC client! :) If you want to buy, check the curves and invest.