I guess it depends on the type of music one is writing for. The analog sounds are great for certain type of music. I do have some Arp, Oberheim and Prophet samples somewhere - not that I use them very often.
As for realistic string sounds, modules are still quite limited. OK if making some pop song. But before the days of softsamplers, I believe many people had to go for real recorded chamber strings to attain that sound. No matter how hard we try, modules strings will always sound like it comes from a box. Even softsamplers, even though they are now pretty close the real thing, is still not 100% realistic. Otherwise all the Holywood soundtracks will have gone totally softsamplers. But as yet, many movie composers still record the music from a live orchestra. But then, softsamplers is the closest thing we can have at a lower price (short of paying an entire orchestra for recording).