I imagine that all dogs are different...but here are the essentials in my house.
*easy to grab rubber ball for fetch
*big floppy plush squeeky toy (almost as big as she is) that is fun to shake around
*rope "bone" (the kind with a knot at each end)
*a Nylabone (the blue nubby dental kind)
*nubby ring with a squeaky toy attached (I'm attaching a picture of just the ring but they make them with a plush squeaky attached that those are way more fun)
You can get some wonderful stuff at wal-mart. Their plush toys are loosly-stuffed so they are great for shaking. And they have good rubber balls and rope bones. The rest of this stuff I had to get at an actual pet-store.
Sydney likes toys that are big so that she can drag them around and they "fight back". And she is a huge chewer so that's why she likes the Nylabone and the nubby ring so much. It's really cute and funny to watch her rummaging around in her toy box to find the toy she is looking for.
I'll attach some pictures of her favorites next week but I don't have any on my computer right now.
Good luck finding out what Elbow likes. I hope this helps.