There are 3 basic collar choices:
The Button Down Collar: This is the least dressy of the 3 choices I'll mention. If you're wearing it with a suit, you should pick a broadcloth material. An oxford cloth is more casual and isn't your best choice for a suit. Medium width ties go well with this collar.
The Straight Point Collar: Probably the most common of collars. Conservative and safe. Goes with pretty much anything and is a great go-to shirt. Works with all tie sizes and knots, and is probably your best choice if you're going to wear a narrow or skinny tie.
The Spread Collar: The most confident and stylish of the 3. Looks great with medium and wide ties. I prefer the traditional overhand or four-in-hand knot; the windsor (especially the double) can get really bulky, and I like the shape and asymmetry you get with a four-in-hand knot.
There are also 3 kinds of cuff to consider:
The Single Button Cuff: The standard. Definitely the most common, and on less expensive shirts, this is probably the cuff you'll get. But it's nice and simple and goes with whatever.
The French Cuff: The most daring. Also the most formal, although you can successfully dress a french cuff shirt down if the links are right (subtle and subdued). I favor more subtle links with a suit too. I love wearing cuff links, but I try not to be showy or flashy about it. Do it right and it's a nice, classy look. Pair your French cuffs with the wrong links (usually the big, gimmicky, flashy ones) and you'll look like a tool.
The two-button Barrel Cuff: A great look. These cuffs look especially nice with the modern, streamlined suit, but they look good with anything.