Let me preface this by saying that I only build with DT Swiss. There are other spokes out there and I'm sure that they are pretty good but DT is well known and readily available.

Having said that, DT Alpines (2.3/1.8/2.0 mm) really aren't much more expensive than DT Champions (2.0 mm) per box at A.E. bike for example. Both of these spoke types are much less than Competitions or Revolutions but, personally, I think the DT Alpines might be the best spoke available. They aren't any heavier than a 2.0/1.8/2.0 Competition and they are much stonger where it counts...at the head. The fact that the spoke head fills the hole at the hub (usually you have 0.3 - 0.5 mm of play) means that if you do end up with a loose spoke, the spoke can't move around much and doesn't break as easily. I riding a mountain bike wheel made from the Alpines that's over 5 years old and it hasn't given me any problems. Before I would expect to pop a couple of spokes a year.

Alpines aren't that well know (I'm working to change that ) and are a little harder to find but once you use them, you just don't see a reason for going back.