More specifically, one of the most brilliant sci-fi RTSes to ever be made. The plot was involving and fairly complex without being incomprehensible. The ships were awesome. The tactics were involved, and the long-term campaign strategy was amazing (your fleet carried over between each mission, so if you fucked up somewhere and lost a bunch of ships, you'd be going into the next mission with a battered, understrength fleet). Salvage corvettes (nothing as satisfying as seeing your dinky little salvagers steal an enemy cap ship from under their noses). Insane, distantly-related religious fanatics living in a nebula, with thousands of fighters and mothership-class ramming vessels. Multiple missions with creepy, not-well-understood threats that had to be approached very carefully, because "blow them away" just plain didn't work. A space RTS released in 1999 that basically perfected three-dimensional combat in one shot (all the maps were perfect spheres, and the resources/objectives were scattered throughout, not just along a horizontal plane). A certain mission took place in a three-dimensional junkyard maze full of autoturrets and the Dog, while you were operating with fairly limited forces. An enemy that ended up not being a faceless mass. Multiple other enemies with no relation to the main enemy. The Bentusi. Kamikaze attacks. Kamikaze attacks with your harvesters blowing the shit out of enemy ships.
I still have the disk, and I still play it from time to time. Homeworld is easily on my top 5 games of all time, and I will never have trouble finding praise for it.