I buy SD's somewhat often. If it's not on BLU and not coming in 1-2 months or so, I'll buy.
For instance, I was in Best Buy today and they had season one of "My Name is Earl" (24 episodes) on sale for $19.99. Dropped in my $5 off card and walked out with it for $14.99.
The other day I found Jumanji in the $5 bin at Wal-Mart, so I bought it.
And I got Heroes season one in SD.
My oppo HD981 does a great job of upscaling, so why not buy the stuff that I want.