German-English Dictionary
I am looking for a good German dictionary. There are three types I would like to have referred to me particularly.
1. A dictionary that is very comprehensive and contains some scientific words(an equivalent of a college dictionary if that helps)
2. A dictionary that is meant for younger children and does still contain a lot of larger more specific words but lacks the scientific words
3. Though the above would be nice with an English translation to it, I would like to make a separate section for that. So please also recommend a good German-English/English-German dictionary as well if you can.
Thank you for your time.

Question

German-English Dictionary
I am looking for a good German dictionary. There are three types I would like to have referred to me particularly. 
1. A dictionary that is very comprehensive and contains some scientific words(an equivalent of a college dictionary if that helps) 
2. A dictionary that is meant for younger children and does still contain a lot of larger more specific words but lacks the scientific words 
3. Though the above would be nice with an English translation to it, I would like to make a separate section for that. So please also recommend a good German-English/English-German dictionary as well if you can. 
Thank you for your time.

Answer

Steven is right - Duden is THE authority to go to for German: if it's in the Duden, it's accepted German.
If it's translation you're after, IMO Pons can't be beat (and I used to work as a translator). For technical and/or scientific terms, best try www.wordreference.com and have a look at the discussions if need be.
Sorry, no idea about dictionaries for children.

Answer

I always use  this: 
 http://de.thefreedictionary.com/
GERMAN-GERMAN , online , and free.

Answer

I only use online dictionaries. Dict.cc is good but very full of translations which can be hard to tease out sometimes; Leo isn't bad and has nice links to Etymology, Pons is good too. But depending on your level of proficiency, Duden is the best. It's not a translation dictionary but in my opinion is the real authority. Maybe I'm just old-fashioned. Plus all the explanations are in German, which I like because, even though I'm a native English speaker l, I hate the English language. Just my preference.