Cast on's are one of my obsessions.
i think that for any thing that hangs around the face (neck bands of sweaters or brims of hats) its important to have a special edge.
if you are doing a brim up (to crown) hat, these means a special cast on..
1--Long tail is OK
2--2 color long tail (use a CC for thumb, MC for index finger) is better--
the CC can be a different color, or angora or fun fur, or chenille, or (the list goes on)
Don't want a CC?
3--then try the Twisted (aka German, german twisted, norwegian, norwegian twisted, etc) Long tail
4--or how about a braid cast on? (yet another version of Long tail) it, too usually is done in colors (3 to 5!) but it can be done with multiple strands of a single color.
(and there are other variations of long tail that are very pretty besides these)
5--Or try a channel island cast on.. Very stretchy, pretty petite picots.
6--Or a tubular.. (that goes into a 1 X 1 rib, and the ribbing ends with an eyelet)
Which cast on is so dependent on which cast ons you know!
(A--know what they look like, B--know how they behave, C--know how to do!)
you can look on my blog my 4 part series
about cast on--at the bottom of each page there is a link to the next part-- (part 4 is a collection of links to tutorial and reference) or look in my photo gallery
for some ideas in use. (i have also just started doing some video's of cast on's my self!)
Hats are a perfect venue for learning new cast on.. and they show off fancy needle work!