Let me recount one of the most fun experiences I've had in a game. A long long time ago, in a galaxy far far away, there was a lone, Imperial Starbase orbitting an Imperial stronghold. It was a dull day, as usual for this starbase. It wasn't responsible for producing any of the mighty ships of the imperial fleet, nor were any based here. It was just a simple outpost, guarding a remote sector. Until, of course, a Rebel contigent of blockade runners and frigates, accompanied by a few squadrons of fighters dropped out of hyperspace. I thought my space station was doomed. Little did I know how well the station alone could defend itself.
In Empire at War, space stations can call in a limitless supply of reinforcements. The level of the station determines what kind of reinforcements it can call in. The smallest stations have only fighters, while the bigger stations can call in Acclamator-class cruisers (the ships the clone troopers shipped out on in Episodes 2 and 3), each of which also has a squadron of bombers and fighters. These space stations, if used properly, can defend your sectors with relative ease. I've had one amazing showdown between a large rebel fleet, including Home One and another Mon Cal cruiser, and my lvl 5 space station. I won, but not without taking a lot of damage. The defensibility of the space station makes defense a fun task, instead of a chore.
I have to admit, this concept is only really applicable to space and sector-based games, and it very well may only work well with a game like Empire at War. However, I think it is a very awesome feature, and certainly makes an enemy assault fun, instead of something to dread. The dread comes in when your space station is damaged heavily, and your reinforcements are minutes away.