I've been thinking about mass training here lately, and have put together a few nuggets of info that may prove useful.
1) When it really comes down to it, all performance in any strength sport, bodybuilding included, comes from maximal strength. So, as bodybuilders, at least some portion of your training should involve weights at 90% of your 1RM or above.
2) For the actual growth of muscles, you should do as is prescribed here: a few sets, to failure, in the 5-12 rep range, and allow recovery. The amount of weight you can lift in these "bread-and-butter" workouts is going to be affected by your maximal strength; so, having higher absolute strength will translate to more growth stimulus in the long run.
3) If your muscle tissue can't support added mass, you won't grow. There are several "support" factors that can be influenced by training.
Capillarization, for instance, can be stimulated by ultra-high-rep sets (40 or more); more capillaries translates to more tissue that can be supported. This process generally takes about 2 months to complete.
Satellite cell fusion is also an issue; this is stimulated largely by a growth factor called IGF-1, which is released when the muscle is damaged in training. The best way to do this are to emphasize the eccentric portion of the lift. However, any lift that maximizes the TUT or tension-time curve will have this effect. The important thing to remember is to minimize negative training, as it can be detrimental if done consistently.
4) The hormonal spike caused by heavy training with compound movements may on the surface seem to have little effect on results. It is true that circulating hGH appears to have little effect itself on muscular hypertrophy. However, it does stimulate production of local IGF in the muscles; when this is applied to a post-training state, it may well prove beneficial.
5) Insulin has anti-catabolic effects, as many of you know. However, it has been shown that consuming carbs during training may actually help stave off training-induced catabolism, and thusly help in training.
6) For those that do cardio, interval-type training may be of interest, as it has been shown to reduce fat stores while sparing muscle. Additionally, it helps to raise work capacity by conditioning the body to perform multiple periods of intense work.
This effect can also be applied to weight lifting. By simply shortening rest periods to 45-60 seconds, not training to failure, and doing 6-8 sets, you can effectively increase a given muscle group's work capacity. This can be applied between growth cycles, or as a plateau buster.
7) As far as exercise selection or number, this should vary frequently on maximal work, but infrequently on the growth sets or the anaerobic threshold sets. That's not to say you should never change; but that you're better off keeping with the same exercise and just changing the something about the total training volume to continue progressing.
8) You don't always have to go to failure; there are occasions when leaving a little gas in the tank can be beneficial. Simply shortening the rest periods and/or adding a set or two can keep the exertion level high without providing all the negative effects that going to failure causes; this is the same basic idea as not doing negatives all the time. Alternating periods of high-exertion and low-exertion can be more beneficial than going all-out every time.
9) It won't hurt to incorporate other types of training into your routine on occasion; training with Olympic lifts, or other "unorthodox" methods can be of benefit to bodybuilders. You don't have to do it all the time, but it can provide a nice change of pace.