One thing and always amazed at when people ask about dust collecting is no one here has any idea of your shop size, no one knows your work habits. No one knows what tools you have and want to connect. So as all the suggestions you will get are just that suggestions. But let me throw some facts at you. When you say dust collector, what tools are you running that is producing dust and if they are where are they producing it??? Most tools such as planers, tablesaws, bandsaws, jointers, scrollsaws, drill presses do not produce the dust you are talking about. They produce chips and larger pieces of material. Your tools that are hardcore dust makers are your sanders. They are the ones that you need to focus on. Now what you also want is to scrub the air so an air cleaner is more important. All the tools that I mentioned that are more chip makers do produce dust also to a degree but look where that dust comes from. Top of the saw, top of the planer bed, and so on. These tools have dust ports but that is just a place to catch the debris off the bottom of the blades. What happens on top needs more duct work and gadgets to collect the fine dust. No shop is dust free no matter what collector you use. You will not be using more than one tool at a time unless you are multi person shop. So do not go crazy on and get caught up with bigger is better. Size it to your largest chip producing tool and include the pipe run. There are formulas and believe one of those links has them. No need to take 6" hoses to a machine. If you can make your pipe run 6" and drop off with 4" and at times 2" for smaller tools. But again pay attention to the true dust makers, the sanders.
Gee I forgot the ever popular lathe. A lathe is a chip producer and the dust comes from the sanding portion done on a lathe. Zeroing in on how you collect that dust will help with any sized dust collector.
