Congrats, and I cooked with mine for the first time last week. Keep the Thermopop, as an instant read is invaluable for doneness and food safety (although save for the thermopen as it is worth it as well!). Get the remote thermometer as well if you can. As the others have said, Maverick makes a good one, but so does NuTemp, Weber, Thermoworks, etc.
When I started smoking, using good thermometers to learn the relationship between pit and food temps was invaluable to learning how to run my smokers. Running the WSM last week was the first time I used my remote thermometers in a couple of years, as I had no idea of how it was going to perform.
Congrats and can't wait to see the pictures!
Nauti-Que BBQ Team
Pitmaster and KCBS CBJ & CTC
Lang 60 Marie Laveau
Deep South Single Chamber Glenda
WSM 22.5 Asmarelda
22.5 OTG Samantha