What a tough question! It really depends on what I'm making. I like cotton. I like alpaca. I really don't use much acrylic except for the occasional blend or novelty item. I like wool too. So I had to think about the yarns that just begin to look lovely as soon as you have an inch or two and that is wool. But I think I really prefer wool blends, like Lambs Pride I just love the wool and mohair. I'm currently making something with Elizabeth Lavold Silky Wool. It's lovely, the only problem with it is that sport wt. takes forever to knit! Alpaca and silk is also lovely.
I haven't been able to use much in the way of wool yet - way too expensive except for the stuff I find secondhand.
I found some lovely grey stuff one day at ValuVillage. It was very fine and I'm not into that but I bot it anyway and knit my Mom a pair of socks using it with a soft acrylic.
I figured it would give the cheap acrylic some strength and it did, besides adding a nice colour combination.
I'm always buying acrylic - mostly because it washes so easily and it quite cheap by comparison.
One day I'm hoping to buy some sock yarn... LOL!
TEMA since you live in Canada have you checked Elann's website? They have very good prices on a lot of different yarns. I bought a bunch of superwash sock yarn for $2.30 a skein. Even after paying shipping to US I thought it was a decent price. They also have tons of free patterns using the yarns they sell.
"Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it's the only thing that ever has."--Margaret Mead
I can't choose! I like them all. Depends on what I'm making. Wool for felting, warmth in scarves, hats, and mittens; acrylic and acrylic blends for afghans and kids things because I can wash it and also because I can afford it LOL; cotton for dishcloths, potholders, and tote bags, and even clothing if it's soft cotton. I haven't tried alpaca yet but I have a wool/alpaca blend in my stash that will be a hat and scarf set one day so I'll get to try it soon.