I can't or don't want to get Helix off the net. You can get by with 16Mb of RAM, but 32Mb is much much nicer and probably what most people would consider a minimum now.
Many people like more.
If you want to compile the sources yourself, you're looking at 200Mb. If you are running Linux, you probably have it already. Announcements of individual package updates are posted almost daily. This applies to people running any of the above except Debian. I can't or don't want to get Helix off the net.