With a front-mounted hitch, though, you can keep the winch inside and just hook it to either the front or the back depending on the needs. The downside is there's one more thing in your car taking up space and becoming a projectile in a crash.
Come-alongs (hand winches) are less than ideal for many reasons I've listed in another reply to your comment. The better solution is to do your best to not need one.
http://www.harborfreight.com/1200-lb-capacity-cable-puller-3...
http://www.harborfreight.com/4000-lb-capacity-cable-winch-pu...
http://www.harborfreight.com/8000-lb-cable-winch-puller-543....
http://www.harborfreight.com/manual-strap-winch-95541.html
It's only $15 for the cheapest one (they have other types too that mount to the car). Also get a long strap to go with it in case the nearest tree is not close.
You don't want an electric winch anyway - you never know if you'll have power in an emergency.
Generally speaking, if the engine can't start/run, and help is nowhere to be found, winching the vehicle out will be more trouble than its worth. The best part of an electric winch is you may use it in conjunction with the engine when solo, meaning you can generally free the vehicle as soon as you find some traction, rather than constantly advancing, re-entering the vehicle and checking for traction again.
But you're right about and additional strap: one should always have with their winch, at a minimum, a tow strap and a tree saver (plus requisite shackles, snatch blocks, and gloves if using wire rope, or rock guards with synthetic). I once got stuck deep in a ravine, and 150' of synthetic rope fell short of the nearest tree by 5 feet, but a tow strap and tree saver made up the difference and I got to sleep in my bed that night, rather than in the jeep.