I didn't see the Cygolite at the URL you provided, but they're pretty good as far as function goes, or so I was told by the guy who works at Incycle. I actually considered buying one because, at the time, it was the cheapest with the best performance, but, if I remember correctly, I shyed away from it because it looked like it was constructed flimsily. That was 3 years ago, and I think it cost, then, $99, or $110. I'm not sure how they're made now.
Man, there are a lot of affordable high power lights these days! 30w NiteHawk for $99! Wow! I wonder how they're made though? I can't tell from the picture if they're "plastic" (meaning cheap), nylon (great), or metal (also great). It looks like the lights mount below the bars, which is kinda cool.
2.5 lbs is heavy? My Insight is a NiMh and I don't think it's any less than 2.5 lbs. I don't even notice weight. Anyway, as long as not on your head, 2.5lbs is pretty light.