I am a suspension noob - so hoping you guys can point me to right direction. In the near future, I am looking to replace my factory suspension to get a more comfortable ride, without sacrificing the stock towing capabilities. It appears this has to be some sort of air system where you can adjust the stiffness on needed basis. Unless there is a good bang-for-buck suspension that can give a good compromise on both. The max towing I do is two motorcycles or a fishing boat. One of the things I would definitely want is to level out the front. I am not looking for huge lift - just level the truck out.

My truck is a 2004 F150 FX4 with Crew cab (I think..). It has four doors, but the two back doors can open only after the front doors are open and they open like suicide doors. It is also a short bed.

Any suggestions will be greatly appreciated. Do not have a dollar amount in mind, but would like to stay within $500 for parts.

 

You have a SuperCab (SCab for short). Two full size front doors, and two half doors that hinge in the rear. SuperCrew is 4 full size, front hinged, doors.

Anyway, for a level kit, look into Rancho's Quiklift Loaded system. 2" front level and the shocks have a 9 position dampening setting. That'll keep the front end nice and cozy. The pair of fronts, including the coils, will run you about $400 + the cost of an alignment.
An air system is going to take up most of the $500 you want to spend. Firestone makes a Ride-Right system that is pretty popular. There is also a site sponsor here, Air-Lift I think it is, that has some kits.

 

Thanks for your advice. Going to a suspension shop this weekend to check out what they got. But wanted to arm myself with a few options.

 

I got the rancho quicklift loaded on the front. Part number for your truck is rs 999910. I have really liked them. They gave me right at two inches of lift.