Neolithic sites: Clava Cairns, Easter Aquhorthies and Loanhead of Daviot recumbent stone circles
Pictish stones: Sueno's Stone, Rodney Stone, Picardy Stone, Maiden Stone, Dyce Stone
Medieval ruins: Urquhart Castle, Spynie Palace, Duffus Castle, Elgin Cathedral, Balvenie Castle, Huntley Castle, Tolquhon Castle, Kildrummy Castle, Glenbuchat Castle, Dunnottar Castle
Intact castles: Crathes Castle, Drum Castle, Fyvie Castle, Corgarff Castle, Cawdor Castle
Jacobite-related sites: Culloden Battlefield, Fort George
Picturesque Moray coast villages: Pennan, Gardenstown, Crovie, Portsoy
Best (and most expensive) distillery tours: Glenglassaugh, Balvenie, Aberlour
Best cheap distillery tour: Glenfiddich (free!)
Best food and drink: Highlander Inn, Craigellachie; Mash Tun, Aberlour; The Anderson, Fortrose
Just scratching the surface. See
Undiscovered Scotland for details on these, and many, many more ideas.