I can't say enough how much I truly love the Ratchet and Clank series. The humor is great, the gameplay is amazingly fun, I could replay this for months and months. One of the best gaming series ever :) This walkthrough here is for Ratchet and Clank 3 - Up your Arsenal. If you're looking for the older walkthroughs, they are here:
Ratchet and Clank Walkthrough
Ratchet and Clank 2 Walkthrough

Basics
Key Combos
Weapon Listing
Equipment Listing
Skill Point Listing
Titanium Bolt Listing
How Health Works
General Screen Layout
Vid Card Listing
Box Listing
Starship Upgrade Listing
Trophy Listing

Planet Listing
Starting the Story
Veldin
Florana
Starship Phoenix
Marcadia
Marcadia - Laser Defense
Annihilation Nation
Aquatos
Aquatos - Switching Roles
Tyhrranosis
Daxx
Obani Moons
Blackwater City
Holostar Studios
Zeldrin Starport
Metropolis
Zeldrin
Quark's Hideout
Aridia
Phoenix Battle
Nefarious BFG, Koros
Mylon

NOTE: I list where I ended up getting nanotech / health improvements as I progressed through the game, but of course depending on how many times you replay a mission or what order you do things in, your mileage may vary. My notes are just to give you a general guideline. Always buy armor upgrades whenever they are offered, they are critical to survival.

When you beat the game once, you can restart at the beginning with all your weapons intact - plus you get new MEGA weapons to buy!! Note you can only get a MEGA weapon if you have a fully powered up weapon at the end of the first pass - so make sure to upgrade all of your weapons!