I would go for the traditional signaling sources, and stay away from flares. Pea-less whistle. Signal mirror. High intensity LED flashlight. Ferro rod with striker, Bic lighter, waterproof/windproof matches, candle, tinder (for starting signal fires in addition to warmth/cooking). Also one of those thin mylar "space blanket" type things - silver on one side, blaze orange or gold on the other if you can find that, for signalling and also for warmth. A good 4" or so sheath knife is wonderful for all kinds of things (improvising things for signalling too) in a survival situation. I sometimes even take a small packable ultralight soft kite (parafoil - no rigid frame) on hikes. More often used for fun, but could be an awesome signalling device too. e.g.,
http://intothewind.com/Item--i-5152
And don't forget, let someone know your plans. Where you intend to go, and on what time schedule.
[ EDIT - p.s., If you try the kite thing, definitely go with a parafoil. Don't go with a "Sled". Sled kites are frameless too, and cheaper than parafoils, but they don't fly nearly as well and take some skill. Parafoils just fly themselves and can be staked down and left unattended as a signaling device. ]