Another Bose-X alternative for those with a slightly smaller budget is Lightspeed Zulu. I haven't compared them with the boses but I have a mate who "upgraded" from Zulu to Bose-X and promptly switched back to Zulus. Anectdotal evidence of course, YMMV.
I bought a used pair for about half of retail price and they've served me well even though I'm utterly careless with them.