You should take it from someone who has been around all sorts of shops in his career — I've worked in scene shops, cabinet shops, and industrial shops. If you want to turn your garage into a wood shop, you need to build it around your table saw. The time that you spend looking, the time you spend comparing and finally making this crucial decision will pay off for you in the quality of your finished product.
Truthfully? The bottom line is that you should buy the best you can afford the first time out. It will save you time and frustration — or worse — the heartache of having to replace a poor machine with a better one.
There are two basic types of saw: the contractor saw and the cabinet saw. If you've spent time perusing the inventory at your local Home Depot, you are looking at a contractor saw. Most of these machines are made for light duty and soft woods, for use in an outdoor or on-site working environment. As basic wood shop tools go, they are functional for making long rips in 4x8' sheets of material where your margin of error is in the 1/8 to 1/16th inch range. They are lightweight, inexpensive, and frequently sold with a mobile, often collapsible base. This can be an advantageous selling point if your space is at a premium.
The main drawback to these saws can be found in their basic design. The motors tend to be underpowered, the tables are frequently made of either plastic or aluminum — which is great because it's light, but the surface will require constant maintenance to keep it smooth. Finally, the all-important fence is frequently substandard for accuracy, too light to hold heavy lumber in place, and too easy to knock out alignment.
The better option is to take the plunge and buy a cabinet saw. You won't regret it. These tools are universally sold with a polished cast iron table, and the best ones come equipped with a minimum 2HP motor that runs on either single phase 220v (readily available in your garage, although you might have to run a new circuit) or three phase power. They are designed to cut any material, whether it is plywood for the kids' playhouse or heavy hard woods to build that perfect coffee table. The fence systems are built to provide accurate measurements to 1/32" or 1/64th" and maintain their alignment with the heaviest 12/4 stock you can run. Also, unlike a contractor's saw, a cabinet saw can cut accurate bevels to 30 degrees, over and over without worrying that the blade traverse could slip -- something that is problematic with even the best model of contractors saw.
Ultimately, the final decision remains with the person who will be using the tool. Of all the basic wood shop tools you will buy, this one purchase will make or break the quality of your hard work. The table saw is at the heart of your shop -- virtually every piece of finished wood you take pride in will have come into contact with the table saw at least once, often multiple times. And the versatility of the saw becomes more apparent as you gain experience.
You can get by with economizing on your other machines — I personally use a contractor grade 12" power miter saw that I built a long feed table for in lieu of a radial arm saw, and I got lucky shopping for some of my other basic tools on Craigslist (but let the buyer beware!!!). Yet when it came to this one purchase I absolutely refused to compromise. The price point for a good saw can run between $1200 and $3200. Mine ran about $1600 new, and I spent an afternoon in the electrical box wiring up a 220v power feed for it. It was money and time well spent.
In conclusion, when it comes to selecting your saw, this one purchase merits the time you spend researching, asking questions, and considering your long-term wants and needs. It's at the heart of your shop, I can't stress it enough — take your time and make the best decision that you and your wallet will allow.