If I have 5 ETH I will do a in depth research for ongoing or upcoming ICOs. I will consider factors such as sustainability of the project/company, whether it really delivers a valuable service/outcome, will there be a demand for their tokens in the future, whether the team has experience and qualifications to handle the project, whether token/ICO price is reasonable etc.

I will pick around three good ICOs in different industries and rank them according to my research. I will invest around 3 ETH to the best ICO and 1 ETH per each for the next two ICOs. I have seen projects such as DigixDAO and 0x did really well after the ICO.

The issue with holding 5 ETH is that ETH already appreciated and it will appreciate slower rate which means I have to stay for a long time to take a considerable profit.