Another option
Hundreds of pilots at NetJets, including myself, are using a combination of the Bose QC-2 headset with a boom mike kit from uflymike.com. The boom mike is very high quality and has a jack for an MP-3 player. The QC-2's are $300 and the mike kit is about $200, so you can have a Bose ANR headset for half the price of the Bose X. It takes a single AAA battery that tends to last me about 7 flying days. I also use the headset when I'm flying commercial and with my XM-receiver during my layovers. Probably the best investment I've made in a long time.
-NTFB