Highest resolution timer, but includes overhead from other tasks. Still I found it to be the best. Using SetThreadPriority() to bump up priority should reduce overhead from other tasks.
Supposed to exclude overhead from other processes, but seems to include interrupt overhead. timeBeginPeriod() (requires a later timeEndPeriod()) can be used increase the tick rate, but this also seems to increase the reported time, indicating that interrupt overhead is included in the process times.
A more generic time call. On Windows XP, reports time in milliseconds, but appears to be based on a 64hz ticker.