> I always find the believability lacking in sci-fi that suggest a civilisation capable of faster than light travel could possibly be interested in trading commodities or manual labour of another.
I think the Stargate universe solved this well; the civilizations capable of building FTL drives (including the one that built stargates themselves) didn't need to trade much with anyone (one of them did use slave labor from other worlds, but for somewhat plot-justifiable reasons). Humanity used increasing amount of FTL tech over the series, but those were either stargates, borrowed, stolen or donated tech, not something humans built themselves - and thus humanity did interplanetary trade.
> the only thing we posses of possible interest, would be our (and our planet's / ecosystem's) uniqueness
That's the core point in David Brin's Uplift saga - ecosystems were the most interesting things a species would own (or rather, lease).
I think the Stargate universe solved this well; the civilizations capable of building FTL drives (including the one that built stargates themselves) didn't need to trade much with anyone (one of them did use slave labor from other worlds, but for somewhat plot-justifiable reasons). Humanity used increasing amount of FTL tech over the series, but those were either stargates, borrowed, stolen or donated tech, not something humans built themselves - and thus humanity did interplanetary trade.
> the only thing we posses of possible interest, would be our (and our planet's / ecosystem's) uniqueness
That's the core point in David Brin's Uplift saga - ecosystems were the most interesting things a species would own (or rather, lease).