Hmmm...I don't seem to have much in the way of centrepieces. In my big tank, it would probably be my male bristlenose- he's a handsome fellow!- except he spends all his time in the amphora, fanning his babies. Oh hang on, perhaps the amphora can count as a centre piece. Or better, amphora with bristlenose known to be in it.
Fry tanks don't have centrepieces, and fish that hide (species tank) don't really make good centrepieces either. In the cory tank, my big anubias plant might be the centrepiece, instead of an eyesore, now the young bristlies have cleaned it.