Come on then Rich, Which tv series first coined the phrase?
Anyway, Lifting depends on what you want to do with the truck, and why you want the space. So I will give you a quick run-down on pros and cons.
BODYLIFT - These are spacers, that lift the body further away from the chassis - if fitting these, body mounts must be solid, and you must fit rubber bushes each side of the spacer - you may even need to reinforce with a plate before hand - 2 inches max.
This effectively gives you more space for axle articulation - or more space before the tyre rubs on the arches. You vehicle will look higher, you have a few more inches before the water starts creeping in, and the best bit, it gets rid of mud traps between the chassis and body, as you can clean and paint the chassis tops easily.
DON'T think you can handle deeper ruts - the chassis is the same height from the ground, as are the diffs, and you engine is the same height, so don't fall into the 'water isn't getting in so I can go deeper' trap!
You can improve matters by getting bigger tyres, and bigger wheels. this may give you an extra inch....you will lose your gained articulation on the wheel arch fouling though!
SUSPENSION LIFT - Longer springs and shocks will give you better articulation, and raise your vehicle and chassis further away from the ground. This is better suited for off roading, and you will be able to handle deeper ruts/water crossings without fouling the chassis....don't forget your diffs will always be the same height as before (unless fitting bigger tyres) so look at diff guards.
You will need to extend your brake lines, especially the front. Your ride will be softer and have a much more 'boaty' feel, so be careful on corners - you either bias for on or off road - that is the pay off. Also watch for side angles - the higher you are, the less an angle you can successfully reach without falling over!
Rule of thumb is 2" - That is Useful, without being detrimental to ability. You can pull another inch with tyres/wheels.
Suspension kits are around £5-600, Body lifts kits around £60.