It's fun to explore and analyse each Terran unit, and building tech tree; but more thrilling to find out new changes to the tech tree, and figure out strategies with the newer units and their abilities/upgrades.
In old-school Starcraft: Brood War, you needed to build a Command Center, and a Silo add-on, plus a bunch of other buildings to build a Nuke. Its cost in minerals, vespene gas, supply depots and time length was more than it was worth if you lived long enough to even attempt that strategy route. A two-word sentence can make dreaming of nuking your opponent nigh impossible: Zerg Rush.
With StarCraft II, all those "gosu" Terran players are up for some awesome Nuke galore experience if you manage to build your initial defense/offense to go with the Nuke Strategy.