I am curious to know what different weight paper is about. I see advertised 80 lb, 140 lb and 300 lb paper but wonder what effect this will have on my artwork... also coldpressed and hot pressed. I think I understand that one is grainy and rough surface and other is smooth... I prefer a little texture and the paper also must be strong because I make changes and need to blot with fresh clear water... sometimes/often :)

also what about long term (10 years, example) concerns for future value of my watercolor art work and what will maintain color and like-new look the best, assuming artwork is not framed or vacumm sealed somehow.

I like yassy russian pans to work with because colors are intense and have an attitude, (much like me):D

I was reading about the hot vs cold press paper just last night. I'm a novice so take this post with the intent to share information.
The advice is from Barbara Nechis' book "Watercolor; the creative experience' page 11. I don't recommend this book, I would just look for it in the library.
'D'arches 140 pound cold press can take a fair amount of scrubbing for correction, and it's smooth but absorbent surface is ideal for fluid washes.. . Hot-press surfaces are totally non-absorbent. They are ideal for ink, line, and painting where crisp edges or scrapeouts are needed.. . Rough paper is excellent for stressing testure. Graded washes take a little extra effort in that the white bumps of the paper tend to reappear unless they are strenuously covered... '
Somewhere I read that the higher the weight, the more water the paper can absorb and the longer the painting can be worked during one sitting.