How much of a difference does yarn really make?

[sixtyspink]

Hi,

I am a fairly new knitter. I began with a scarf in garter stitch, with a super bulky yarn and size 13 needles.

Now, I can't seem to get off aluminum needles. I have tried bamboo as well as plastic, but they seem to pull on most of my yarn and give me a very loose, uneven stitch (most of my yarn is wool or a wool blend.) It just turns out looking lumpy, unlike all of the projects I have been seeing on here, which are lovely and even and well...wearable. Could it also be a problem with tension or are alumninum needles really just easier to work with?

Does the type of yarn used on bamboo needles really make that much of a difference or am I just a bad knitter?

Also, I am stuck living in a town where the only access I have to yarn is at the neighborhood Michael's, which seems to be lacking.

Any suggestions for a nice yarn to keep my eye out for?