There's no such thing as "best HYIP". EVERY HYIP will scam eventually. Only question is whether you're going to be in profit or not. When it comes to a particular HYIP, take your pick from this or "HYIP Advertisement" section.
I guess Sinip is right about HYIP, epsecially now that there seems to be problem with the E-currencies being closed down by Big Brother everything looks dim right now and playing with HYIPs is not a good idea for now.