tsl's advice is good as far as it goes but if you want wheels that are truly tough, go with DT Alpine III. There's a couple of reasons, both related to the manufacture of the spoke. The spokes are 2.3mm/1.8/2.0mm. But the process of rolling the threads on to the spoke make the threaded end of the spoke close to 2.3mm. Since the thread is larger than the overall spoke diameter at the head of conventional spokes, the eyelet at the hub has to be larger so that you can pass the spoke through the hub...usually around 2.5mm. With a conventional butted or straight gauge spoke this leaves a gap between the hub eyelet and the spoke. As the wheel rotates around, the wheel naturally deforms with tension decreasing slightly at the bottom of the wheel and tension increasing slightly at the top of the wheel. That extra 0.5mm allows the spoke to move in the eyelet and can lead to fatigue at the elbow and broken spokes. If the tension of the wheel is low, it's worse than if the tension is high.

The Alpines fill the hole more so that there is less ability of the spoke to move in the eyelet. Less movement means less fatigue. The elbow of the Alpine III is also thicker and stronger than a 2.0mm spoke so it resists fatigue better. Less fatigue and more resistance to what little fatigue the spokes experience, why would you chose anything else?