I've been in this position. If you can truly afford it, go with a new truck. But, if you have any plans in the near future that may change your financial situation, then go used. I had a real nice '96 when I graduated from college, then had to let it go to buy my first house. Then I recovered, and bought an '02. Loved that truck, but then had 2 kids. Now I have a first gen.
Bought mine for $8500, and have around $17k in it total. I don't buy used, so I bought new seats, tires, wheels, etc. I'm at work or spending time with the kids, so I don't play mechanic, so I also paid a shop to fix a rear main, KDP, etc, etc. If I had gone with some used parts, and did the work myself, I likely would have less than $13 in the truck. Tough truck though. Hauls more than my previous '02.