Should I be buying food/water/guns/ammo?

Personally, I prefer to buy guns from private individuals. Reason being is that if the Gov't. does decide to confiscate your weapons, private firearms transactions are not recorded. And don't brag to anyone about what you have. People will sell you out to save themselves. Sounds paranoid, I know, but it may be the difference you need to survive the coming years.
Good Luck

Dont really know anything about survival. I am just starting to really consider this myself so my comments are what i have learned along with what is common since. In typing this I am also thinking it through to myself.

I heard guns: I agree but also know your neighbors with guns and already have a semi plan amoung yourselves.
Food is life: no what canned food last the longest. Start a small garden even if it is in barrels in the back patio. know what has the highest yeild/is easiest to grow. Learn how to perserve, and freeze dry. Always have bleach on hand for sterilization.
Water: I don't hear anyone talking about having a hand pump to get water when the electricity is unavailable. When I was a kid alot of folks had old hand pump wells that we primed with rain water and drank from.
Stay in proper training - Your life may depend on being in good shape. And even if the S don't HTF you will enjoy you life much more.
Make a list and keep it in order. Much of the stuff you will need you will be able to aquire at the closing bell by quick response. Those who are not prepared will be in panic for a few hours. Be prepared to act quickly.
Get a floor safe and put keep as much cash as you can on hand.

Very important: Don't talk about what you have guns or otherwise. Keep it to yourself. Remember what the Outlaw Jose Wales said, "Now remember, things look bad and it looks like you're not gonna make it, then you gotta get mean. I mean plumb, mad-dog mean. 'Cause if you lose your head and you give up then you neither live nor win. That's just the way it is. lol
Get a dog to warn you of approaching danger.

Most important - get right with Jesus Christ
What happens on this side of eternity don't really matter much if we are right about the second comming of Jesus. If there is no eternity the it don't matter much either. Peice of mind is a pretty valuable thing. Seek to know Jesue Christ. What do you have to lose?

With the POSSIBLE financial/social meltdown that we MAY face in the coming months/years, how many of our fellow citizens are getting preparations in place?

In my neighborhood, we've formed a link of cell phone/e-mail contacts of about 60 homes to notify of any civil unrest, large or small. Some homes have weapons, some not, but all have able bodied patriots ready to defend our community. If things get bad, and the police are not able or willing to assist, are you ready?

Ask yourself what YOU would do if a group of people came to your house and demanded food and personal possessions.

In our network, we'd have at least half show up within minutes.

Originally posted by Double Eights
Should I tell my parents to stock up on food, water, guns, and ammo? ...

Yes. It's almost too late.

Originally posted by StonyJ
Ask yourself what YOU would do if a group of people came to your house and demanded food and personal possessions.

In a SHTF scenario my personal possessions would be pretty much useless, as for food about 97% of it is stored elsewhere.