Choosing gear and clothes or recommending them is a complex task. There is a reason your average REI is the size of a supermarket and yet doesn't come close to carrying everything available-there are dozens of manufacturers and hundreds of choices for almost everything you could want, from cheap mass market products to high end specialty products made by small companies. You can spend anywhere from $40 to $1000 on a sleeping bag for example.

I've collected my small set of gear and clothes over many years and I couldn't begin to tell you what to buy. I could tell you what I would buy, but that's not the same thing. Before you buy anything more, read as much as you can, books like The Complete Walker. Then, start by listing what you need, not by brand, but by item. Then start looking at brands. Set a budget and prioritize what is most important to you. Don't let anyone in a shop talk you into anything until you do this. Otherwise you may wind up with things that you don't need or don't work together. Right now a pack is the last thing you need. Wait till you have what you intend to carry then get a pack to hold it all.

I will recommend Capilene because I use it, but 4 is expedition weight for cold weather, I think it's too heavy for summer. Other people will recommend Merino wool. Both have their advantages, but I like what I have and have had my set for years.