Here in the Rockies most of my buddies call the Sceery call the "Scary", cause it scares the elk away.
My personal favorites are the Primos Hyper Lip Single with the tone converter. It's a cow call that is the best I've heard and used. You'll not only call in elk, but a lot of hunters too, so be careful!

For a bullbugle, you can't go wrong with the E.L.K., Inc. Power bugle. Buy extra bands in both colors.

Both of these are very easy to use (still have to practice though), and reproduce the most accurate elk sounds out there.

But no matter what you use, you need to study the elk language and "talk" like they do. Calling wrong, or too much, or not enough, or at the wrong time, will be more harmful than if you went into the woods with no calls at all!