Here's a list of first to last stuff I'd (And I AM getting) get:
1.) Hood Shield, also known as "Bug/Rock Deflectors" or "Bug Shields". I think they actually add to the look of the truck. Like S2k said, it'll protect the hood. Price: About $50.
2.) In-Channel Ventvisors, if you like to open the windows, you can then do it when it rains. I think these add to the look of the truck, too. Price: About $50-$90.
3.) Hitch Cover. If you have a hitch receiver and don't plan on using it all the time, get a nice bowtie for it. Price: About $20-$40
4.) Bedmat/Liner. I'm getting at least a bed mat to protect the bottom of the bed for scratches, so I can use my bed. I don't like scratches anywhere. If you get a liner, don't plan on removing it ever because it'll leave a bunch of scratches unless you use a lot of double sided foam tape, and I mean a lot, or unless it's a line-x/rhino liner. I plan on getting at least the bed mat, if not the line-x. Line-x is permanent. Price: About $50 (mat), About $150-$200 (plastic liner), About $300-$600 (Rhino Liner/Line-X)
5.) Tonneau cover. This way, stuff in the bed doesn't get wet. It's like a trunk, essentially. I plan on getting a painted fiberglass one. Price: About $150-$200 for many vinyl ones, About $650 for a folding one, About $700-$1000 for a fiberglass one, already painted to match.
I included prices of the stuff so you know what to expect when purchasing the accessory or accessories.