If you have surround speakers, an SACD/DVD-A player, but no surround-capable amp, yes by all means get one.

Even if you buy no more multichannel SACD or DVD-As, you'll at least be able to play your stereo CD collection in surround by using Dolby PLII or HK Logic 7. Overall it's not good as discrete multichannel, but it can be pretty good.

You can then try a few multichannel SACD/DVD-A releases, but if you don't continue that your new multichannel surround amp will still be used for stereo->surround reconstruction via Dolby PLII or L7.