The Milky Way Is The Only Way: Played straight, given the general uselessness of other experimental fittlers, and since the only reliable form of FTL the universe evidently permits is stargate pairs, the far end of which has to be dragged out to its destination at subluminal speed. Thus, only a veritable tiny fraction of even this galaxy has been explored.
That said, the Elsewhere Society did manage to raise the mind-croggling amount of money necessary to have a stargate pair constructed and its Wandercompagnon lobbed at the Greater Ancíël Whirl (which is to say, the Large Magellanic Cloud) at near-light velocity, but it won’t get there for a long, long time. They’re having rather less success in raising more money to build a second pair and repeat the exercise with Andromeda.
And it’s not like sufficiently powerful telescope arrays can’t see some interesting things going on Beyond The Space We Know, other galaxies included…
Music to my ears. They should create a No FTL Trope over at TVTropes.org or STL Only Trope. It gives any scifi universe a very realistic feel even if one isn’t writing diamond hard scifi.