Skammer posted a really good list for SAR here:
http://www.bladeforums.com/forums/showthread.php?t=482042
I'll take the liberty of re-posting it here, but Skammer deserves full credit - it's a great reference IMO:
SAR Suggested Searching Equipment
The Safety Officer has the responsibility to restrict the un-prepared from wilderness duty. What you and your fellow searchers have on your backs is all that you have when you are finding and caring for the lost subject and each other. Being prepared means you hope for the best but prepare for the worst. Don't be a liability to your team.
In Your Pack
. Food or snacks (Self sufficient for 24 hours)
. Water (2 liters suggested, 3 in heat of summer) and capability to prepare more
. Metal pot or cup
. Several lighters
. Waterproofed matches
. Rolls of flagging tape
. Raingear
. Sitting pad (closed cell foam 12x20)
. Spare compass
. Spare flashlight
. Spare whistle
. Spare batteries 2 sets per unit
. Spare socks
. Spare winter hat
. Spare fleece or wool sweater
. Spare mittens
. Spare pens, pencils, grease pencil, permanent markers
. Several large, heavy duty garbage bags,ideally orange
. Various Ziploc style bags
. Heat reflective heavy duty emergency blanket
. Candle lantern or safety candle
. Duct tape
. Weather proof shelter large enough for more than one person (Tarp, Heavy Plastic, manufactured emergency shelter, etc)
. Para cord, string or twine (strong and easy to use) 50ft minimum
. Signaling devices (flares, glow sticks, etc)
. Folding saw
. Tubular webbing strap (twice arm span)
. First aid kit (made to suit your ability)
. Strong Bug repellent
On You, Not In Your Pack :
. Safety glasses
. Primary compass
. Primary knife
. Primary flashlight
. Primary whistle
. Extra bright flashlight/headlamp
. Survival kit (small pocket kit in case you are separated from main pack)
. Watch
. Personal medication
. Kerchief or Bandana
. Identification
. Notebook (waterproof)
. Pencil or all weather pen
Suggested Additional Items
. Toilet kit (paper, trowel, Ziploc bags)
. Hand sanitizer
. Vinyl gloves
. Stove & fuel or Fire bowl
. Fire starters
. Thermos bottle of hot water
. 8-12mm Rope & carabineers
. Sun glasses
. Binoculars (optional)
. Spare prescription glasses or contacts
. Blanket
. Lip balm
. Sun block
. Safety pins
. Ruler
. Map case
. Multi-tool
. GPS unit
Clothing Suggestions
Orange is the color of choice for any clothing.
. Orange jacket
. Non-cotton clothing appropriate to season and conditions
. Light, moisture-wicking inner layer
. Heavy non-cotton socks
. Warm or cool hat
. Brimmed hat
. Light durable gloves
. Mittens
. Gaiters
. Durable H2O proofed broken in boots (not Rubber boots)
This list is only a guide to ensure a serviceable pack that will keep you and the lost subject safe in severe conditions.