Hmmm, tough one. I love an Opinel too, and a carbon Opinel at that. I've got lots of them, and if I'm ever recommending a good penknife to someoen who hasn't used one before that's where I start. I have a TBS Boar that I bought recently and I'm coming to rally like that, although I've not been massively impressed with the sparks it throws from a ferro rod. I think my favourite sheath knives, though, are probably my old, beaten-to-crap Martinii and my Enzo Trapper with custom scales.
That said, I have lots of other knives that I like - a Claude Dozorme Capucin, an HH edition Liong Mah #5, a Kershaw Reverb.... The list goes on.