I love SACD's, have become totally addicted to the format, and listen primarily on headphones. It is worth it to me. I am sure that not everyone can hear the difference, and would be surprised if one could tell the difference in a DBT (especially against the sort of DACs that Dinny has heard/is used to), but that's because the single greatest advantage I find to listening to SACD is that I find it less fatiguing, which doesn't DBT well.
The only way you can find out if it's for you is to try it. But I'll echo Aardvark Samich's comments -- make sure there's enough out there for it to be worthwhile to you. Some of the back catalog is rather hard to get ahold of. Are you into classical? Then you should have no problems, depending on whether or not you're into the mainstream stuff or the esoterica. (And even if you're into esoteric stuff, just check, it's rather easy -- e.g. search for 'arvo', search for 'dashow'.) Jazz is better represented than pop/rock, but there's some pop/rock out there...as long as you're into Depeche Mode, Genesis, Deep Purple and the Allman Brothers, and less into Pink Floyd, Tangerine Dream, Black Sabbath and Jethro Tull.
And one doesn't rip SACD to one's hard drive entirely in the digital realm, that I know of. Grawk's is the only solution of which I am aware.