How many days after the sell-by date until you throw out food/drink?

Depends what it is.

If it smells okay I eat it!

The sell by date really does not mean the food has gone bad. The sell by date is just the limit in which the store can sell the product. Ground beef and other meats for example can last many months after the sell by date if they are frozen. For other foods like milk and such I would personally say it was still okay after MAYBE 5 days. The sell by date is more of a required guide line for food and drink.

2/3 days, tops.

In 1965 we were eating eggs that, according to the box, were frozen and boxed in 1946. They tasted fine, but it shows you how the US military never wastes money and serves only the best to it's soldiers in battle!
I guess that's how they can afford $350.00 toilet seats.

Straight away.

Sometimes I'll go for it, it really depends on if it passes my investigation.

If there's green stuff growing on it = NO
If it smells off = NO
If it doesn't look like the colour it should = NO
If it's 6 months or more past the due-date = NO

As Ioncecamewaytoohard said, it depends what it is. Eggs are known to last months past their expiration date, various types of meat can be stored a few months if frozen, though careful with chicken. I've heard some horror stories about that.

I find that people these days are way too paranoid about expiration dates. My boyfriend for instance, freaks out if something is a day past its "best before"/"sell by" date even though those aren't even expiration dates. If people started checking what types of food actually last past the dates instead of trusting the dates 100%, maybe less food wood be wasted.

Til it goes bad.

2 days maybe 4 at a push.

After the third day, I'll definitely think twice about eating it. Milk and meat I'm probably not going to take that risk. I've had yogurt that was like ten days past the date and it was more or less fine (although a bit more congealed). Bread I'll toss as soon as I see the first sign of mold (or if it tastes nasty and stale).

Doesn't matter as long as it's not spoilt.

It depends, how many days would you dare me?

About threeish days, it kinda depends on what condition it's in.