I missed a question from the Meme... What knitting technique do you feel is the most valuable?
The long-tailed cast on, no debate.
This is an oft-discussed topic in my knitting classes. I won't let anyone leave my classes without learning it, and insist any sock or mitten projects in my classes start with this cast on.
Why? Three main reasons.
1. The long tailed cast on looks good in an unobtrusive sort of way. It disappears into ribbing, provides a plain edge for stocking stitch. It's nice.
A lot of the beginning knitters I meet use the the knitted cast on. Truth be told, the knitted cast on is ugly. I do teach this one in my beginning classes, I admit, but then we all used training wheels the first few times we rode a bicycle.
2. The long tailed cast on is stretchy. The knitted cast on, and its close cousin the cable cast on, don't stretch. Nothing worse than a pair of mittens that won't go over your hand.
3. It's quick.
I use the long-tailed cast on 99% of the time.
The trick is in estimating how much yarn you'll need in the long tail. Tip #1: keep the tail of the yarn (that is, the bit with the end rather than leading to the ball) close to you. The yarn close to you gets used up more slowly than the yarn away from you. Tip #2: an inch per stitch will do.
But yes, you often run out of yarn before you've cast on enough stitches. Happens to everyone, all the time. And so you need to be able to easily and happily undo the whole thing and start again. It took me three goes to get a long enough tail to cast on for my cashmere hat. It was made worse by the fact that the pattern suggested using the yarn doubled for the cast on. For 112 stitches.
The last time I used another cast on that I can remember was for the dreaded Kidsilk Haze scarf. That yarn is so damned sticky that I knew I couldn't reliably undo it if I ran out of tail during the cast-on. Come February, I'm going to love that scarf, but our relationship had a rocky start. (It's a story for another day.)
But other than that, I'm a long-tailed cast on girl.