Essentials

Extra leaders, small swivels, small tape measure, good net, polarized sunglasses, dry fly floatant, small knife, some small floats, split shot, small pliers, Wading staff,fly patch, and a medium flask of aself selected adult beverage. (strictly for saluting the fish)

Salty   If you get to the Steelhead Big Run there will be plenty of guys there that you and pick their brains and even get some help with casting if you need it.

All the above, plus I always have a needle,(minnow threading type), helps with untying knots, cleaning eyes, etc. I also take some petroleum jelly when it starts to freeze for my guides, works for me. The multi-tool, or wire cutters, are a must. An imbedded hook can happen very easily, and it feels oh so good after you get it out!

good advice, I'd rather forget my flies than my little cooler full of ice, rum, & pepsi.

You CAN carry a ton of stuff.

As far as required...when I pack light, I have:

Rod, reel, small fly box, spool of tippet, spare leader, nippers, hemos, floatant.

Everything else is specialization or convenience (not that its a bad thing!).

Once your vest/pack starts getting full, the weight of items vs. their usage streamside will usually determine what goes and stays.

A few napkins.

Lots of great suggestions so far, although I'm surprised this one has been missed. A thermometer is a must have for me. Oh and don't forget the TP and hand sanitizer too

Reason I carry a cell phone is because I sometimes fish alone, includeing ice fishing, and have a medical codtition that precludes me from walking if a certain thing happens. I once had to have 911 called to get an ambulance and medical help to be taken to a hospital and be treated. I was down and couldn't walk. The downside is that cell service is not always available. I just try and avoid those areas, and try and hook up with someone else to fish with as often as I can. Better safe than sorry, even if your young and healthy, fishing alone or with others, you never know when misfortune can strike. I just bring it along for safety reasons, not to make random calls to chat. To each his own.

I should have made the "For safety reasons" more clear in my first post. I don't even turn it on when I'm fishing, unless as previously stated I need help. It usually stays in the glove compartment in my truck. People driveing, shopping, walking around with cell phone against their ear makes me wonder how they survived before the cell phone was invented. Personally I don't care much to spend a lot of time talking on any phone, period.

bigfoot,
  I totally agree with having a person along.  I can usually maneuver fairly well when I have my pain meds (hell, with enough of them I could ski!) but I always want somebody with me because, like you, if I go down hard, I may not be able to get back up.  Cuts into my fishing time.

ORIGINAL: doubletaper

jack, my kids and mom tell me i should get a cell phone because i hunt and fish by myself so much.
because of the remote areas i go i'de be better off with a fog horn or something to that nature in case of an emergency..

Flare gun.

And a self-defense cheeseburger.

I guess nobody drops their spilt shot.  I always do.   So, I have a bunch extra in the back of my pack.  I always drop the whole thing.  And it's always in fast water.   Probably best to do the same with flies .. I'll say this with caution (I've yet to lose a fly box) but I've went chasing before. 
 
Drinking water, advil.  Polarized glasses got to be up there for me.  Tippet too.  Clippers.  Indy's.  Hemo's.    'Bout it.  I'm not a pack rat, I don't carry much.

heck the more toys ya have the less you get bored lol.just kidding you will know what to carry and what not to as cold said weight versus use.