Of course, different fibers are more appropriate for some projects but if we're just talking which we like best in general, I have a serious alpaca fetish. Lol. I just love it. I love the feel, the weight, the look, even the animals themselves. I have the serious goal of having an alpaca farm one day. Not as a main source of income. I love critters (my zoo of a household reflects that) and I'm absolutely fascinated by these creatures. Plus they produce my favorite fiber!
But I digress... I like working with wool but I have a strong preference for merino, expecially if I'm knitting for myself. (As if that ever really happens. :P) Many wools do not agree with my skin. I wouldn't say it's a full fledged allergy but it's certinaly unpleasant. Merino is wonderful to knit with and wear.
I cannot tolerate mohair or mohair blends. My skin says no, in no uncertain terms. I'm not big on the look of it either though. I like the fuzziness of alpaca but mohair is a bit much for me.
I have not knit with angora yet. I have had a few angora blend garments and don't really care too much for it. I haven't made a decision about the fiber in general yet. I do know I find it only suitable for outerwear. Again, sensitive skin.
Basicly, I could just roll around in a mountain of alpaca and merino all day and be happy. Lol.
I like cotton and silk (in a blend) as well but they're just not as forgiving as protein based animal fibers.
Unfortunately, I currently live in southeastern SC where it's rarely cool enough to wear the things like to knit! sob I'm about to head up to western NC for a couple weeks and I'm so excited to use some (wool and alpaca) handknits!