9-speed is such a crock. I have a bike with each setup (8- and 9- speed), and it irks me that Shimano abandoned quality 8-speed parts. There's nothing discernably improved by the addition of ONE cassette ring. But having worked in marketing in a past life, I understand the market value in introducing something new. Kinda like Campy's 10-spd road stuff (egad).
As far as finding parts, EBay can make your life easier, providing you're patient. I can still find some 8-spd stuff at Jenson or Pricepoint, but it's getting harder to find at these outlets. I see a fair amount of NOS 8-spd stuff on Ebay, and like mentioned before, some of the mega-9 stuff is backwards compatible with 8-spd drivetrains.
I don't mix SRAM with Shimano but I hear a lot of folks have good luck with it. I tried a SRAM PC58 chain on my 8-spd rig, and it didn't like my Shimano drivetrain. I found an IG90 chain online and all is good again.