I got the sig other a carbonation machine for his birthday and I must say it kicks ass, especially for the cost. It came with a sampler pack of syrups and every one we've tried is good. You can also get a shitload of refill syrup...like enough for hundreds of liters for about $25. Also, it's fun making your own soda.
I got this one and it came with a refill CO2 canister, sampler pack of syrups, and water-flavoring syrups....
http://www.amazon.com/SodaStream-Sod.../dp/B002SKHQS4
Also, if anyone needs a recipe for coca cola cake (the chocolate variation that's popular in the South), I gots the hookup