are you male or female?
How old are you?
Where are you going?
Are you planning on going to nice restaurants/clubs?
Look at ebags.com for a good selection of backpacks

Not much. Think of the things you need over a week and just take that. Most people over pack, I WAY overpack so only take what you are sure you will need and use. You can get a good bag at a place like sun and ski or acadamy, I’d recommend an internal frame vs external (you’ll see what I mean if you don’t now). If you do a search on this website you’ll find some good lists that should help you out.

I guess I’d concentrate if what not to bring… avoid things that U’ll use only once, or bulky things… bring layers of clothes instead of heavier jackets or that kinda stuff, especially since U’re travellin in summer.

Once your trip is over 2 weeks long (the max you can carry without doing laundry) it doesn’t make much difference how long the trip is. You need to pack enough stuff for a week and then wash, replace, toss, etc. as you go.