Teletype Corp Model 33 ASR (or ASR 33). My friend Richard VE7CVS lent me his (i.e. we hauled it from his house to mine) and we hooked it up to my S-100 system. A whopping 10 cps (characters per second) chunk-chunk-chunk! I don't think we used the original 20-mA current loop interface, rather a RS-232 serial interface as this was the late 70's or so. Aside: Used at UBC, and I'd find these at some mill sites (eg. Ocean Falls Newsprint) as these used on early Measurex systems.
The IBM Naval Ordnance Research Calculator was possibly the first supercomputer and was the most powerful computer of its time. It could perform 15,000 operations per second, and the first version had 2,000 64-bit words of main memory, roughly the equivalent of 16 kilobytes.