Scion (and apparently recent editions of Exalted?) use an odd system called "ticks," wherein each player has a stack of counters, and when they finish an action, they take a number of counters equal to its speed value, and every one-second action phase everyone throws a penny back in the hat or eats an M&M or whatever to get rid of a counter.
Some useful applications--running across the 7&11 parking lot takes five seconds, but they can interrupt that at any time, so the player counts down until they 1) get there or 2) interrupt to change actions. And the aim rules are very similer between the two systems - one second of aiming, +1 die of accuracy or a +X modifier (X=accuracy of the weapon). White Wolf assumes a few things (like "the wait maneuver takes three seconds but can be interrupted at any time," "the aim maneuver takes three ticks, each tick adds +1 die, but can be interrupted any time"), GURPS gives a bit more flexibility but at the cost of quick simplicity.
I'm still lurving the 1-second action concept--it's tight enough that you get the "feel" of different things happening at different times, rather than the sense that when two combatants are fighting, one barbarian strikes his foe, checks his watch, says "Your turn," the orc says "thanks," stops picking his nose, swings his club and misses and says "Hey, can I do that again?" and the barbarian says "No, it's not your turn anymore. Round's only ten seconds long, dude. You were picking your nose for like half of it. Green on the outside, green on the inside."
So, that's two recent adopters of the same basic round system (cosmetically different, but with the same results). Will there be a third?