we have the Sizzix SideKick, CuttleBug/CuttleKids, ZipéMate and soon the Cricut. Out of those, the CuttleBug and SideKick run for a close no.1. The SideKick because its small and handy for the small projects and quick cut, and the CuttleBug because you can literally cut anything with it with the right dies. We use all Sizzix dies with the CuttleBug including embossing dies.(even those who are meant for manual pens).
I'm thinking of buying the big one for at home but not sure as I have the ZipéMate at home, just dont use it often atm.