I'm no fan of cheap winches myself, because a lot of the offshore stuff uses cheap magnets that crumble or crack. Series wound motors, otoh, will not suffer from such problems, but do run a bit more money. Basically they're a normal shop/grinder bench motor with a bunch of reduction gearing.
http://www.off-road.com/offroad/article/articleDetail.jsp?id=285616A quick rundown. Note - you'll need a heavier electrical system for sure.
http://www.pirate4x4.com/forum/showthread.php?p=7795482#post7795482Typical junk you find and should avoid. I've hear stories of stuff coming out of the box with the magnets broken or lose inside.
http://www.landroverclub.net/Club/HTML/Winch_choice.htmNice read as well. Tons of types actually. You might consider a mechanical drum type as well, or a hydraulic one. These are better still, but can be a bit tricky to set up.
There is also the mechanical pulley or capstain winch as an option. Not very fancy, but sometimes low-tech is better. A lot of off-roaders have something like this as well as a backup in their kit. I've seen the Army use mechanical winches to haul out stuck tanks, so given enough muscle(20-30 guys in that case...), it'll work.
