It all depends on your goal and your budget and your goals. Most leveling kits make the truck ride the same as, if not worse than stock, overextend your shocks and put more stress on your front end components including your track bar as it's now too short.
I run the 2.5" Carli suspension leveling kit with King shocks, an adjustable track bar and a rear mini pack. It's more expensive that a puck-style spacer but the ride quality is compliant and very comfortable on the road while controled with great bottom out resistance off-road. This is one of our more expensive systems but we'll be offering a bilstein 5100 series leveling kit with 2.5" linear rate leveling springs, caster cam, adjustable track bar, and new front shocks for under $900 so we'll have options for everyone!
Here's a link to a thread with pictures and a bit more information for you!
Carli Leveling Kit Sneak Peak!