5. Sit down! Until you're in your bottom gear, there's nothing to be gained from staying in a high gear and standing up, which will adversely affect your next change.
I find this depends very much on the length, steepness of hill and gears available.
If you don't have a triple, then bottom gear might not be all that low. In that case, standing up puts less strain on the knees.
Standing up needn't imply very low cadence, and it can be quite refreshing to get out of the saddle and maintain a good cadence. Good old Lance used this, and his out-of-saddle cadence was often higher than Jan's sit-down-and-grind technique.
I used to commute over a fair climb, Saddleworth moor, on a 3-speed (bottom gear about 40inches). I found that the ideal technique for day-in-day out riding this was to develop an out-of-saddle cadence+gear combo that enabled me to 'walk' up the hill, putting no more effort into turning the pedals than I would if I were walking up a steep hill or stairs.
