If you want to avoid cracked rims, and you don't go with one of those ultra techy wheelsets like the Mavic Ksyriums (which are nice, but don't even ask me what the spokes are made out of...zirconium??), a great, strong, reliable (and less expensive) option is getting a handbuilt set of wheels using an "eyeleted" rim (like you will find on the tried and true Mavic Open Pro). Eyelets are reinforcements added to each spoke hole which vastly reduce the odds of cracking the rim. Add to that double butted spokes (which are actually stronger than straight gauge spokes) and some decent light hubs and you will be grinning!

A lot of wheelbuilders are into bladed spokes these days, but I think the feel of double butted spokes is nicer, more resilient, especially if you are light.

Wheels, imo, are the one place on your bike where if you make the investment, you REALLY notice it in both the quality of ride and the weight lost (assuming you get lighter wheels). Good wheels are the best upgrade you can make to your bike.