My advice would be too go with the AP1's, since they offer all the forgiveness, in which will lower your handicap.  Play these for a couple years and get it down, then I would suggest maybe the MB's or CB's.  If you do however want more work-ability  maybe take a look at the AP2's.  For now though I would definitely go with the AP1's.  By the way, AP1's offer the most work-ability compared to all the other "Game Improvement" irons.

AP1s are meant for a wide variety of golfers.  I've had them since March and my iron play has been very good.  My 7 iron is also much easier to hit vs my other sets so I took the 34H out.  They land the ball on the green pretty softly and have a pretty high ball flight.  They are also pretty workable.  They hit pretty well in a wide variety of lies. 

I would suggest looking at the 962's or 962B's, given your 18 handicap, perhaps the 962's. I have had the B's for 15 years now and feel they are more than worth the price you can get them for. I bought the 690 MB's when they first came out and played them for 2 seasons before going back to the 962B. I've tested almost every iron model Titleist has come out with but have never found one that outshines the 962's enough to warrant buying new clubs. Btw, our 7-time Club Champion and course record holder plays the 962's. I do like staying "up to date" with technology, just bought the 913 D3 in fact, my 7th driver in the last 15 years, but in my opinion the 962 irons should be a part of Titleist's Hall of Fame.

All I'm saying is ask around to see if anyone near you has a set so you can give them a try. If you wind up loving them, you can own a great set of sticks for about $100. 

Best!

Jason

Along these lines, DCI 981 are a pretty inexpensive iron set (the latest "buy it now" price for 2-SW regular flex is $85).  They ARE cast player clubs and have the "buttery" feel.   You have to be a reasonable ball striker to use them.  I had them shortened 1/4" so the P and W played 35 1/4"; however, my Eye 2s won the contest.

Also, 2008 AP1s can be had used for $250 per set on eBay.  My investment for 6-PW was $220 (and that was mainly because the 8 iron cost me $85 on eBay; I picked up the rest of them at Golf Mart for $29.99 each mainly because the set was missing an 8 iron). 

Henry, Your game will change over the next few years as you continue to grow. A fitted set of AP1's would be the best to improve your game. But cheeck with your local pro to get the best feedback about your game and new clubs.

Forget about the AP1s . Buy the ap2s. im also around that age . The AP2s are the right choice.

Henry, I would get fit for the irons. You will be able to have better perforance an dthe will be helpful longer. I have all cb's and you have to really hit down on the long irons to get them up so i would go 4,5,6 ap2 and the rest cb's.