Many routines and training styles work. I have used several with success. That being said, I think standard block periodization is shit. Westside has worked for several people I know, including me in the past, but I find it difficult to gain weight while using it. I have used a modified version of it that uses triples for max effort work and a repetition day instead of a speed day as an off-season routine. This is what I am currently doing. I see the off-season as a time to build on my foundation and stick to fairly basic work.
When training for a meet, I set up a peaking cycle where I add an extra training day to the week and ramp up the volume. During these cycles I add speed work and do specific accessories to fix weak links. As the meet approaches, I taper the volume down and move to singles and doubles for max effort work.
As far as cycles go, I assume you are talking about AAS. That is going to vary alot between lifters, but basics are best IMO. Test, EQ, drol, and tren are the most popular with the guys I train with. Lighter weight classes will be different if weight gain is a concern. Some powerlifters cycle, while others blast and cruise, just like in bodybuilding. It depends on goals, age, experience, etc.