*Note: the following is simply a guideline for how gear should be layered and worn. You may find somethings go better elsewhere. It's ultimately up to whatever works for you.
1st Line - Basic survival gear.
This is the gear that you carry specifically on your body and in your pockets. Theory being that if you're down to nothing but the clothes on your back you can keep yourself alive and make your way back to safety.
map of your area of operation
basic survival kit
water purification tablets
fishing line w/hooks
20' of paracord
simple rations (2-3 Powerbars or the like)
collapsible canteen (empty)
2nd Line - This is your fighting load
This is the gear you are going to use to fight. Usually worn on an h-harness or some kind of vest and also includes your weapon.
Ammo pouches for rifle - Depending on your choice of firearms, this is going to vary. I personally carry 13 magazines for my AR and anywhere from 2-5 spare pistol magazines
Fighting knife/melee weapon - Again, depending on what you choose to carry. I keep a k-bar fighting knife and am looking to add a tactical tomahawk to my inventory.
Water - Canteens or a Camalbak work best.
First Aid Kit
dump pouch for empty/used magazines
spare batteries for flashlight/radio
1-2 MREs field stripped
50' of paracord
extra pair of socks
1 gallon ziplock bags
3rd Line - This is your sustainment load used for extended patrols, your "camping" gear, if you will, carried in a ruck-sack.
change of clothes
sleeping bag w/goretex bivy sack
3 day supply of food
cold weather clothes (if applicable)
Combined, all of this gear works together to keep you in the fight and keep you alive. Feel free to post any questions you might have.
I've actually got a pic of my gear set-up posted on my page, it's a MOLLIE-based system.
There are basically types of gear systems out there right now; the older ALICE-style clips and the newer MOLLIE/PALS webbing. The later usually have more flexibility in how you're able to configure things, but costs more where the older ALICE gear can be found fairly cheap at this point. Really just depends on how much your willing or able to spend.
I've used several packs over the years, the one I didn't care for much was the CFP-90. No matter what I did, I couldn't get it to carry evenly on my back. Currently, I use and updated version of the ALICE pack or a T.H.E. Pack from Spec-ops. I've got more field time with the latter, just remember to take your camelbak off before rucking up.