I love Jethro Tull too! Although I only have Original Masters and Aqualung. I used to have Crest of a Knave on tape once, I want to buy it again.
Oh and yes, Bruce and Steve have indeed very good music tastes. That much is certain.
If you like Crest Of A Knave you probably like Rock Island too. My Tull favourites are Heavy Horses, A, Stormwatch, Songs From The Wood, Rock Island, Thick As A Brick and Aqualung. But almost all other Tull albums are great too.