There weren't speed guns in SA in 93-94...
Anyway, the fastest clocked deliveries are from Shoaib and Lee, who have both broken 100mph (161kph) in ODIs on a couple of occasions. Shoaib did it in the 2003 WC against New Zealand, and Lee did it in two consecutive balls in New Zealand in early 2005. Both those series were ones where the speed guns were quite generous though, which is the main problem with the current measurement of bowler speeds. Some series are "fast" series and some are "slow" series, and that's despite the speed being measured out of the hand and thus the pitch being a non-factor. Can't place too much value on individual matches really, you have to judge speed over an extended period.
Anyway, I'd say the quickest ever would be Thomson fairly comfortably. In the fastest bowler comp in the late 70s he was clocked in the high 140s measured across the length of the wicket. Anyone's guess what his pace out of the hand was, but you'd assume it'd be in the high 150s-low 160s sort of range. To add to that, this was after his first major injury where it was generally agreed he lost pace.
Impossible to judge guys like Gillespie (of the West Indian variety) and Tyson, of course.
Tait's certainly the quickest around at the moment in terms of average pace. Almost never seems to bowl a delivery that's short of mid 140s, while guys like Lee take a bit longer to build up their pace to the 150 range.
