) and I had timid and varied results over time. After watching the course I was convinced to buy the exactly recomended stuff so I would know if the results I'm getting are bad just because of my technique or because of the materials too 
Watercolor paper preferences can be pretty subjective, but here's a rundown on my favorites. I use both hot and cold press, depending on the painting. As Melissa Bailey said above, don't waste your effort with anything other than 100% cotton. You learn and adapt to your paper just like you do with your other tools.
If you want to skip taping down your paper, you can go with 300 lb paper. But say you have a sheet of Arches 300 lb hotpress and a sheet of Arches 140 lb hotpress: the texture and absorption will be different even though you have the same brand and the same surface.
Arches is the workhorse, affordable and consistent quality. Personally, this is the kind I buy most frequently, in full sheets of 10, both hot and cold press. It may be all in my head/nose, but the sizing (animal derived gelatin) smells a bit stronger than in some of the other watercolor papers I use.
I love Waterford cold press...soooo lovely, feels handmade.
I've used a few sheets of Fabriano hot press and been really happy with it.
My friend always used cold press Lanquarelle. Around 15 years ago, she swore the company changed the quality. She bought sheets a few times but each time said the surface didn't feel right. I'd inherited 30 sheets that were a few years old and had no love for them, but she refused when I tried to give them to her. In her mind, they were irreplaceable, in my mind they were taking up space. I started giving her sheets for her birthday. When those finally ran out, she switched to Arches, but she's still nostalgic about her old paper.