Here's a few ideas on how to save some space.
When you install Snow Leopard, customize it. Uncheck any language you don't use, as well as uncheck the printers you aren't using. If down the road you have a new printer, the Mac will automatically download the drivers through software update. This is a great way to save space.
And the next is two software programs. Xslimmer and Squeeze. Both made by LateNiteSoft.
Xslimmer: "Remove unnecessary code from fat binaries. Xslimmer determines which code your machine needs and removes the rest. This is achieved by removing the code inside the Universal Binaries that does not fit with your machine's architecture, a code that never gets executed and just wastes your disk space." It also strips out any language you don't use (you can set it in the preference). That saves a lot of space.
Squeeze: "Squeeze is a background file compressor, which uses the new HFS-compression technology in Snow Leopard to transparently compress the folders you configure it to process. Mac OS will read those files normally, they will just take less disk space."
I have both of these applications and they're both great. I don't see any performance issues either, and this is on a 3.5 inch HD in an iMac.
I'm compressing my Applications folder now and it's already saved 660 MB, and it's not done yet. The savings with both of the applications may not be that great. But when space is scarce every mb counts.
You'll probably save GB's in XSlimmer, just from removing the languages alone.
http://squeezeapp.com/
http://www.xslimmer.com/