As far as products to recommend, it totally depends on what you're trying to do. Does the car need to be polished? Are there defects (such as swirl marks) that you're trying to reduce/remove? Are you simply trying to prep the surface for a coat of wax/sealant? I think the question is way too open ended for a simple answer.
One of the statements that you'll see around here is that the perfect finish is a process, not a product (can't remember who the quote should be attributed to, Jngrbrdman, i believe). The Deep Crystal system is not my favorite, but as evidenced by du3ce's pictures, you can still get very good results with it if your technique and process is sound.
My recommendation would be to spend some more time reading the posts here, and definitely check out all the articles in the Learn section. This will help you figure out what steps you need based on the finish of your car, and then you can pick some products to use.
I have mentioned a couple of times that I need to know what you're trying to accomplish with a particular product. That's key. Just applying the Deep Crystal polish because you think it will make it look *better* will usually lead to extra work. This will lead you down a path of using multiple products simply because someone on this board said they're good products. However, without doing the research and understanding what you're trying to accomplish with the products, you won't realize that several of the products in your process are redundant, or worse, working against each other.
Hope this is helpful.
John