Shuffle is pointless with such a large collection. If I'm in the mood for trip hop, I don't want Built to Spill popping up in the middle. I do shuffle within genres (I use a two-level genre system) which alleviates that problem, but it's still not a good way to "get in touch" with my collection.
I am going to commit to listening to and rating at least two albums each day, chosen from the genre of music I am in the mood to hear at that moment, with strong preference for stuff I'm not already familiar with. It's a start
In the meantime, I've already grabbed 4 new albums today, and I'm still at work!