Brock05,
I spent a lot of time (2 months) researching what paint to use and tried to make an informed decision based on what I could learn. Your question is not a simple one. You will get a lot of conflicting answers. I'm fortunate to work with an automotive paint expert here in the Detroit area who could advise me on all of my quesions. Here's SOME of my lessons learned...
Paint - there are several different paint choices - lacquer, acrylics, enamels, and urethanes. Within those choices, there are more choices like 1K or 2K (2 component paints use an activator); single stage or base coat clear coat; durability; gloss level; etc. By the way, 3 quarts should be more than enough, add 1 quart of activator and you've got a gollon to do at least 2 coats with plenty left to touch up with. Then there's the primer...
Primer - Todays paint coatings are formulated as a "system". The data sheet for the top coat will have listed recommended primers. Ask the paint guy which primer can be used over your existing paint to provide good adhesion.  

ON'T MIX PRIMER TYPES AND TOP COAT TYPES!! (It's like "crossing the streams". It's bad, very bad - remember Ghost Busters).
So what's the best? 2K urethanes (that's not an opinion, that's test data), but they are also the most expensive.
How much do you care - I figured that it was worth my time to use the best paint and good equipment the first time to get good durability, fade resistance, gloss, and flexibility.  

o you plan on beating the hell out of your truck? Maybe 1K single stage paint is right for you in that case, but it will not hold up well to the elements. It depends on what you will be doing with your rig and how much maintenance you plan on in the future.
Time - I have some serious doubts about getting a good looking paint job in a weekend. I'm assuming that you will be disassembling the front end and the hard top completely. There's a whole weekend in prep work alone. Then you have to let the paint dry for a few days before you can put it all back together. Plan on having your truck down for a while.
I myself used a PPG system: CRE-904 primer (2K) and for the top coat AUE-300 (also 2K). It's an LIC (light industrial coating) and I used it because of it's excellent rust inhibitive and durability properties. I got a lot of orange peel because it was my very first painting experience and it was very thick paint, but I can buff out the orange peel if I want. I stayed away from clear coats because I know that I will be touching up a lot (you cannot paint over clear coats, you have to sand the area off completly before you paint).
Start by looking at data sheets. They will give you an idea of how well they perform and what it takes to put them on. If you can't get a data sheet, don't use it. Here's the link to a site that has data sheets for what I used for reference:
http://www.ppg.com/cr-refinish/phase1/frmFindProduct.asp
http://www.ppg.com/refinishftpsite/docs/LIC_CRE904_907.PDF
http://www.ppg.com/refinishftpsite/docs/LIC5_AUE300.pdf
Hard top white - Use the same kind of paint, so you can use the activator for it (assuming 2K here). I used a common formulation that all manufacturers are familiar with - "Appliance White". It looks very good in my opinion.
Sorry for the long response - there's a lot to think about, I hope you can use some of what I learned. Good luck!