One of the best cooking tools I ever got, was last Christmas, a ThermoPen.
No it's not cheap at almost $100 for a cooking thermometer, but DAMN is it fast, from room temp to accurate meat temp in under 3 seconds. Certified within .7 degrees F. Water resistant so you can wipe it off, batteries are supposed to last 1500 hours, and yeah it comes in about a dozen different colors. 3 seconds to accurate reading and I'm not kidding, You don't have to keep the grill or smoker lid open 20-30 seconds to get the actual temp, just 3 seconds to stab the meat with the micro thin tip (why it's so fast/accurate) take a reading, then quickly close the lid.
VERY cool packaging too..........I think you all should get one for the wife for christmas, and store it next to your grill/smoker.
ThermoWorks - The New Splash-Proof Super-Fast Thermapen
Amazon.com: Splash-Proof Super-Fast Thermapen (Purple) Instant Read Thermometer, Perfect for Barbecue, Home and Professional Cooking: Kitchen & Dining
To sum it up, YES the Thermapen IS worth it...........how many over-done ruined steaks/roasts do you need to burn instead of monitoring them FAST and ACCURATELY.