So many different file formats...

[TheMadMan007]

So it looks like there are a ton of different file formats being used now, and I'm honestly confused as why. If someone could just answer a few questions, I'd think that would help out everyone here. I'm going through and wanting to make my set complete and want to never touch it again after this last round of updating, so having the best files would be nice, running on a top end PC, so space and hardware isn't an issue. Using Retroarch for primarily everything unless it doesn't have a core, then I'll use the most popular/best choice. 

1. For PSX what is the best file format now? CHD? PBP? SBI? Bin&Cue?

2. For Dreamcast, is .gdi the best or are there CHDs now or something else everyone is using?

[Lordmonkus]

1. Bin + Cue is the most compatible and should work with all emulators, atleast all the popular ones. PBP and CHD are compressed so they take up less space but not all emulators support them. CHDs can be converted to a Bin + Cue, not sure about PBP though. SBI I know nothing about, never seen that format before.

2. Like Bin + Cue, gdi are most compatible are the format the best quality rips are in. CHD is the same as they are for PS1, not all emulators support it, is smaller file size and can be converted if needed.

[TheMadMan007]

Excellent, that's all I needed to know. I'll stick with my bin+cue files then. 

[Chris Kant]

SBI is the disc copy Protection file. Unsure if only in Europe available