There's always a  set of irons that's just right for you. The type club, the iron, makes up 70% of your clubs in the bag and like any club they should right for you. Once you have bought a set of irons, if they were not fitted for you, get them fitted. We are not all the same and it would be impossible to make a set of clubs that fitted every one, or a company made a set of 100's of variations. Fitting means the right length of shaft, grip size, and perhaps each club needs slight bending to get the sole flat on the ground at set up. Th information below will give a sense of what you might be looking for.

Types Of Irons

Forged

Forging a club is the original method of making clubs and and in a way is like the blacksmith used to do. The hot metal is sunk into a rough shape and then hammered until the coorect shape. The maker recieves the raw forged shape and the carbon steel or chrome club is finished by milling, griding, sanding, and drilling. Generally is a softer metal with a smaller sweet spot but more 'feel' in the shot. Forged irons are aimed towards better players who place importance on the feel to be able work shots and control trajectory.

Cast

This type of iron involves pouring the liquid metal into a mold. Producing the metal through a mold means that the manufacturers can make more complex head designs. Therefore, cast irons are more suited to the design of today's irons that are perimeter weighted and intricate. Generally cheaper than forged as the productions costs are lower. 

Designs Of Irons
  
Blade

The blade is a straighter less complicated design with the even distributed across the whole club, with the sweet spot in the middle of the club being quite small. Shots hit from the centre of blade are said to fly straighter and longer than other clubs, but the down side is that are more difficult to hit from a consistency point of view, and the 'off centre' shot will be relatively weak.
The blade iron is more responsive to the 'working the ball', ie trying draw fade hook or cut when needed, so suits a lower handicapper.  

   
Cavity back or perimeter weighted.

The cavity back iron is made from stainless steel that offers a harder hitting feel golf shot. The iron distributes the weight evenly around the perimeter of the head, producing a larger 'sweet spot'. In the increased sweet spot reduces the feel but increases the forgiveness, so is better suited the higher handicapper.

Hybrid Irons

A combination of a part wood part iron, the are aimed at the player that struggles to hit the long irons. Even PGA Tour players have replaced the 1 iron in their bags with a hybrid iron of sorts. Also easier to get out thicker rough. The center of gravity is lowerd in the club to produce an higher shot which is better for the mid to high handicap player. 

Note on shafts: Please see shaft guide as there are two main types: steel and graphite and is important in your choice of clubs.