Club Head

A set that is fitted for your swing. I would say a more player-ish iron with a Center of Gravity that isn't too low. Cavity backs can have too low of a center of gravity and cause you to hit the ball too high for your swing speed. I played a game improvement iron, even with a low launching heavy golf shaft and the ball just went way too high for me.

If you are not hitting your irons far, and you are a 5.6 I would say that it is probably your swing over the equipment.

go hit several and see which you like.  i usually go to golfsmith and luckily one of the courses here has most clubs to try.  indoors is great but i like to see the flight outdoors.

not sure what our handicap is but i am a 15-20 and i am currently gaming the TM RSi 1's.  for me it came down to these and the ping G30's.

if you're a better player, i would check out the mizuno MP line.  those clubs are beautiful.  not sure why but i love the simplicity of the new nike vapor irons also.

check out the golf digest hotlist - it just came out as well.

just saw you are 5 handicap - i would check out the mizuno MP line for sure.  the semi-game improvement irons may help with your distance.  i have heard good things about the TM RSi 2's as well.

If you have a pro you work with, have a swing check to make sure you don't have a swing/setup problem.

But, as saevel suggested, I suspect with your clubhead speed applied to R-flex shafts/cavity back head you're ballooning shots.

A few years back I was still playing S-flex for my clubs. When I would travel and get to play golf unexpectedly, the clubs I rented were usually R flex. I found I was "swinging easy" with the lighter feel, and losing about a half club in distance in the irons.

With your driver clubhead speed, the combo of stiffer and heavier iron shafts + heads with a lower VCOG might allow to have a more efficient swing.

In short: Get a swing check, and then get fitted.