Gear preference varies from person to person. I second Kacey's suggestion to check with others at your school. See what they paid and what they like and don't like about what they got.
Here are a few of my thoughts on gear.
Regarding dipped foam vs vinyl covered, vinyl is usually more durable, but there's one big drawback. Many vinyl pads have nylon where they contact the skin. This type absorbs a lot of sweat and starts to smell pretty badly after a while. Dipped foam can just be wiped clean. If you get dipped foam, try not to crease it. Many people smash their gear in their bags or wrap them up tight with the straps. When foam tears, it's usually at the creases.
I've seen people say that brand doesn't matter, but it does, or at least it can. As a rule, cheaper brands are lower quality. Sometimes that means a higher chance of structural defects. Sometimes it just means cosmetic blemishes. If you buy cheap, no-name gear, you'll probably be okay, but with name brand gear, your chances are better, and the manufacturer will stand behind their product. Of course, this isn't a hard and fast rule. Your mileage may vary.
Regarding contact lenses, I assume your worried more about scratching your eyes than losing the lenses. Either way, Kacey's suggestion about sport goggles sounds reasonable, but I have no experience with them. I think most lens wearers don't do anything special and are okay, but there's always a chance.
Most basic head gears will not include any face protection, but there are options. Some have clear plastic shields or metal cages available that can be attached. Some have shields or cages built in. Cages tend to be heavier, but they're stronger. Shields usually have better visibility but can fog up. Full face heads with cages tend to be better balanced than open face heads with cages. Shields are light enough that balance isn't so important.
Good luck!