In the CRJ, I've used both the Telex 750 and 850.
Both are very light, comfortable and fit easily in my flight case.
The 750 (no ANR) is barely adequate for the CRJ, and I suspect that at high IAS the background noise getting in exceeds the threshold for long-term safe exposure. You definately get enough background noise to contribute to fatigue. ($200)
The 850 is more comfortable around the ears and blocks enough outside noise to eliminate any hearing-loss concerns and to reduce fatigue. Also the ANR is powered by the headset (or mic) connection directly from the aircraft, so no batteries to worry about. ($400).
I stayed away from the larger units due to cost, large size, and batteries but if you want a silent ride Bose is probably the way to go.