Following on from last night's shocking benchmark...
Obviously after a good night's sleep I realized that it makes a lot more sense to fix our in-house module so that Date::Manip can be removed from calculating today's date.  So, after a quick two line change (now using perl's localtime instead of Date::Manip), I ran the same benchmark again:
Benchmark: timing 20000 iterations of Time::Piece, DateAndTime.pm...
Time::Piece:  8 wallclock secs ( 6.44 usr +  0.65 sys =  7.09 CPU) @ 2820.87/s (n=20000)
DateAndTime.pm:  7 wallclock secs ( 7.64 usr +  0.00 sys =  7.64 CPU) @ 2617.80/s (n=20000)
Now that's more like it :-)