Quinnell Wrote: So if BTC is traceable, what's the best digital currency that would be fully or mostlyprivate?
There are a bunch, it really depends on what you prefer in features. The mainstream pick would be Monero, but it is definitely not "the best" or most feature rich as there are always new ones being released. It has however been around a long time. It has it's own pros and cons.
Keep in mind there are many more factors that come into play. Just because it's a "privacy" focused coin doesn't mean you are private.