Niggles: Is that Hitman Contracts worth it?
Short version - Yes.
Blithering version -
Hitman 47 = nice game with large levels but it can be vary hard and the lives system always threw me.
Hitman 2 = good storyline and level design but some levels are a real pain.
Hitman Contracts = mostly a repeat of 1 but the levels are new, fresh and it has more ways to do things. Also lost the lives system for the best.
Hitman Blood Money* = fantastic story, better detection system and large open levels.
Himan Absolution = heavy story direction, smaller levels and the best detection system. There is little replay to the game though as the levels do not allow for you to take in other weapons and are rather short.
Hitman Blood Money is my personal favorite, but when Contracts comes here I will be buying it for $10 without issue even given the age of the game, so I hope that helps.