nocheatplus The trick is, its very powerful, and must be configured to match the way your server operates - out of the box its not tooooo bad, but, out of the box configuration doesn't really match the specifics of any one server that may require lengthening or shortening some time windows, or adding a higher threshold because of the way your server behaves and players play. Be warned though - the majority of pvp-based hacks are not stoppable by anything- in theory some hacks could be stopped, but they would impose so much lag on the server at all times from the computational work required to detect them it would impact everything much worse. It is just the nature of the beast, the majority of pvp hacks work in ways that can not be programmatically detected or blocked effectively without influencing regular gameplay, and not discriminating pvp cheat behavior from movements and behavior that likely is to occure just from walking and jumping or swimming in regular play.
Also try AntiCheatPlus. Also if you are running Craftbukkit 1.8, I have experienced some bugs with NoCheatPlus when opening/closing doors.
@scrollbar That plugin is for 1.7.9-, the comments of the plugin page are spammed with people asking about bugs/help requests. NoCheatPlus is the best these days.