For several years, I used a 22 quart pressure canner that I had already for a kettle. It worked just fine, and a standard paint strainer bag from the hardware store fit it perfectly. I moved up to a used 32 quart kettle that I bought from someone in the HB club, and bought a Wilser (sp?) bag to fit it, and I like that better because I can do larger batches and the bag is sturdier, but it other than that it really doesn't work any better and it takes more fuel to fire the larger kettle.
All roads lead to beer

You adapt your process for the types of beer you like, the yeast you use, and the equipment you have. I've gone back to using 2 fermenters (in the bad old days we called the 2nd one a "secondary", which it seldom is unless you're brewing something weird) I start out with a plastic bucket (and if it's the right kind of yeast, which it seldom is, I top-crop it.) After a week or so, I transfer to a carboy and airlock and add a tablespoon of sugar*. When that's finished and cleared, I bottle directly from the carboy, and I pour the sludge at the bottom into a sanitized mason jar and put it in the fridge. I usually don't save the trub from the bucket, but if I do I usually wash that because it's full of hops, grain dust, cold-break protein, and other crap. That's what works for me; you might come up with something totally different and better for you.
*the sugar is to energize the yeast and get it to consume oxygen the beer picked up during the transfer. That's my theory anyway.