Paul:
CD Redbook will be the standard for now and the near future and is where your preference should be. SACD's and HDCD are nice to haves, nothing more or less.
I have owned a SACD player (SONY SCD 555 ES) for 5 years now and the buying and tracking down of SACD's is a pain. I find myself buying titles (usually by mail order) more because I bought into SACD, than because I would normally buy these titles in the first place. For me, with the exception of the RCA Living Stereo, Dylan, Stones, Renee Jacobs' Opera series and the odd Byrds or BST release (and they are all hybrids), there is not much available that I would NEED to have.
I currently own SACD and DVD-A players and owned a HDCD player, with HDCD being the format I liked the best.
If I had to do it all over again, I would have passed on SACD and spent the money on a much better redbook player. It's not that what I own is shabby, but the $1K or so could have been spent on other components.
Regards, Rich