My favorite piece of tech gear is my Garmin Forerunner 620 with its light weight and small form factor. [$400; buy.garmin.com]
Compex Sport Elite electronic muscle stimulator is an essential item for recovery after long training days. [$849; shopcompex.com]
FuelBelt Super Stretch Race belt, a handy pouch that allows you to store gels, salt capsules, etc. [$20; fuelbelt.com]
Electrical tape. You never know when you will need it.
Petroleum jelly is great for preventing wetsuit or speedsuit rubbing and as chamois cream on race day.
A straight-edge razor blade, because if you have a flat with a tubular, it is easier and faster to cut the tire off than trying to rip off a glue tire. Make a cut that is perpendicular to the tread of the tire then you can grab the inside of the tire and simply peel off the tire from wheel.