Teva sandals - ideal for muddy
conditions and cheap
Various synthetic blend shirts. I like these because full synthetic shirts are kind of shiny. These are only 25% cotton so they still wick material but look like regular shirts. Canvas brand which is a copy of AA basically at half the price. You could also go with merino wool stuff like icebreaker, but it's 3x the price. Maybe get one of them.
Pants: Prana Brion pants are amazing - all tech fabric and still slim for 1/3 the price of outlier. Eddie Bauer Guide Pants are similar but I haven't tried them out yet.
Underwear: Any synthetic works fine. Exofficio boxer briefs are popular, I thought they were good but nothing crazy.
Jacket: I have a Marmot Precip I like that's lightweight and
rain proof.
Backpacks:
For my main bag I go with an Osprey Porter 46. If you need something for longer hikes look at their Farpoint instead.
For a daypack I'd find something in the 20-25L range. I have an Osprey Daylite 13L, but find it to be a bit on the small side.
Electronics:
Obviously pack a smart phone / laptop / tablet / camera / whatever you want
Get an external battery !!! These will give you 2-3 charges on a phone. It's great for long bus/train rides, but also in hostels when you want to lock up your phone and charge it without worrying about it being stolen. I use an older version of this one: Anker 6000mAH