I'm an firmware and embedded systems designer moving all my tools from Win XP to Ubuntu. Now using Ubuntu 12.04 (the software center is !great!), took a while to get used to Gnome 3 but since it supports dual-screen monitors it's good for coding debug and (ahh) circuit boards (Eagle). I prefer to work really low-level as micro-power systems (Xilinx coolrunner, arm7, arm15, and lowly PICs in 5-pin SOTs) are my speciality- used for remote telemetry systems.