I'm surprised nobody has mentioned TinyCore Linux. Not everything about it is suckless, but at least it's frugal on resources once you get it configured how you like.
For my development machines, I started on RedHat in the 90s and continued on with Fedora until I found Crux around 2002. Loved it but maintaining and upgrading between versions is iffy. Finally converted Ubuntu around 2008. Been stuck with it ever since. Got a bunch RPi's I play with that have Debian, XBian, XBMC, etc. Experimented with TinyCore Linux, Slax, Arch, CrunchBang, others. I also maintain a few VPSes with Ubuntu. I eagerly await the victor of sabotage/Morpheus/sta.li. I'd love to get simpler and not get hit by the systemd bus. I guess we'll see who comes out on top. What I'd really like is a statically linked Crux built on busybox or toybox or sbase/ubase running the system/root binaries off a RAM disk and apps off SSD. For day-to-day stuff, I use OSX (Mac Mini & Mac Book Air). It's just too easy that way.