I already posted these on a similar thread but i'll just pst them here again
this backpack we got as a gift from my mother. It's awesome with a shade and everything. It is VERY easy to adjust. It also has a large pocket right under where the babe sits that can hold all his gear, his cloth diapers a few changes of clothes etc...
this is a stroller we have as well and it's Kool Stop liek the back pack you linked to. These are nice because the model my sister handed down to us can carry up to 150lbs. My husband and i plan on me carrying the baby and pushing the stroller full of water and that heavy but important to have kind of junk.
If you had to pick only one to get i'd get the stroller. You can always tie a plastic bag with your childs stuff onto your bag for sling it on the stroller with the rest of the stuff it's holding. I say this because you can always tie your child on your back or front using a 4-5 yard lenght of cloth or even a sheet would be perfect.
http://www.wearyourbaby.com/Default.aspx?tabid=196
that shows a few styles of a more intricate back carry but it really is easy to learn/use and I do this with my baby (now 10.5 months old) all the time ESPECIALLY when i'm doing stuff around the house. He's calm out f the way and I can get shit done

All i did for the cloth was buy a few yards of some fabric, cut it down the middle and i have 2 wraps. (P.S. if anyone wants one let me know) You can also carry like a lot of women from africa do which is just to tie or tuck the cloth just above the breasts (think like you do with a towel) Here are some video demonstrations with that as well.
http://www.wearyourbaby.com/videos/Tors ... pbStep.MPG
I also have a ring sling that fits across the the body and cups over one shoulder. I find this the easiest to learn first and to get in and out of.
Message me if you would liek to know more