Congrats on the new saw.
This article has some good, low-cost tips for setting things up:
http://www.woodmagazine.com/wood/pdf/delta/ds-038free.pdf
Most of us have a bunch of tools and accessories we thought we couldn't live without, only to find that we can.
My most-used TS setup tool is a plastic drafting triangle. It was inexpensive and has been very accurate. When I set my blade to 90º, I know it's dead on. Same with 45º. I don't think I've ever built anything that needed any angle other than those two, but I also have a Beall Tilt Box that I bought years ago thinking I might need one.
I purchased a dial indicator and fancy machined bar for making sure my blade and fence were accurately aligned with the miter gauge slots, but I see the article above has a very workable alternative using a piece of scrap wood, a screws, and a miter gauge. It's very important to get the blade and fence set up to be parallel with the miter slots, but it's not necessary to spend a lot of money for the tools to do it.
On the subject of miter gauges, I HIGHLY recommend investing in a good aftermarket miter gauge. I love my Incra 1000 SE. It's one of those tools I can trust to be dead on, every single time. I added a sacrificial fence to mine, and I wouldn't use any miter gauge without one.
Another TS accessory I wouldn't want to be without is my GRR-ripper push block. I've used push sticks -- both shop-made and store bought -- since the 1970s, but they don't offer nearly as good of control as the GRR-ripper.
I respectfully disagree with Ryan about making a zero clearance insert. At least for my Ridgid TS, it was much easier and more accurate to purchase one. (For my saw, I'd need to have a bandsaw and router table to make my own. I didn't have either of those tools when I first got my saw. Other saws might have simpler throat plates.) I started out with a HDPE throat plate from Peachtree, but didn't like it because it had some flex to it. I eventually bought a couple of phenolic plates from Rockler about 10 years ago, and have only used one of them so far. The one I use has only been used with thin kerf blades, so the slot hasn't gotten any wider with use. I use one of my old plastic Peachtree throat plates for dado cuts. (The flex isn't really a problem with dado cuts). For 45º cuts, so far I've just used the metal throat plate that came with my saw. If I ever have a project that will require more than three or four such cuts, I'll bust out my spare phenolic plate and cut a 45º slot in it, but so far I've not really had the need.
I totally agree with Ryan regarding the Freud blades. Great bang for the buck, although I use one of their mid-level models. I don't have them handy to tell you the model name or number, but I think they are the Freud "Industrial" blades. I'm not sure if the Big Box stores sell them. I've bought mine from Rocker and Amazon. When I was making a lot of cutting boards, I was consistently getting rip cuts that were glue-up ready. Scott Spencer is our resident TS blade expert here. Search the forum for some of his reviews and comparisons of various makes and models of blades.