Pack: I'm using this pack, despite it's weight, because I sweat profusely, and the fully ventilated back panel helps me from soaking through my shirt and the back of my kilt when hiking. I also like the pack because it's my 3 season pack, during the summer I'll be hiking with 5-6L of water and feel that this pack will support that weight better.
H2O filter: I don't like waiting 30 min for water, it's as simple as that.
Camelbak Thermobak: The insulation is great for preventing my water from becoming overly warm, which makes me less likely to drink it.
Cookset: I tend to boil in a bag, along with some easy frying pan food, so I need the pan, and the bowl makes drinking coffee while water is heating for breakfast much easier.
Towel: yeah, I can probably ditch this.
Soap: this will be included in consumables
TP: no, I didn't add TP to this list, as it'd be under consumables, however I WILL be carrying it, mainly because the plants around here tend to either A: not have real leaves, or B: have very big thorns, or C: a combination of the first two.