Nice Tolkien library!
I have both the Silmarillion and the Legend of Sigurd and Gudrun, but haven't gotten around to reading either of them yet. Frankly, the Silmarillion looks kind of intimidating; I've heard it can be a tough read like Sir William said. Legend looks really good though.
The Silmarillion reads much like the Bible does- and I've read that extensively in my youth so I haven't retained all that I've read, but the overall tone I still carry with me. Not to mention the layout. Still, if you can get through it, the Sil is incredibly in-depth...I'd even venture to say that the reference books that are largely put together by his son got their start from the texts that ultimately became the Sil.
And I did not actually read Beowulf, not in its original form...I read an Anglicized version that was more story than poem (I don't like rhymes, the use of different meters et al, never have) which made it more palatable for me.