The Wikipedia claim of increased jitter over S/PDIF Toslink seems to be a bit out of date as it was a more suitable explanation of the phenomenon in legacy D/A converters which weren't as good at clock recovery as modern circuits.
The case to be made for Toslink lies in its electrical isolation...
You haven't mentioned what speakers you are using. Those may be the weakest link. However, assuming you have decent speakers, I would target that receiver. Getting a newer digital-capable receiver should offer you a lower noise floor, thereby taking advantage of the clean digital S/PDIF outputs...