The 7-30 Waters is never a bad choice.
Though most will not agree, if you are going to mostly be shooting Varmints with an occasional Deer thrown into the mix personally I would prefer something along the lines of a 6mm-223, 6mm T/CU or even .250 Savage. Granted these are not offered as standard T/C Production Chamberings, and some may say they are too light for Deer sized game, they will indeed do the job provided the range is kept within reason, the right bullet is used for the task at hand and that bullet is put in the right place.
Personally if shooting Varmints I would perfer a 14" .223 Remington or one of the 3 cartridges I recommended, and for shooting Whitetail Deer I would prefer the 7-30 Waters or the .30-30 Ackley Improved (the .30-30 AI will offer a velocity gain over the standard .30-30 Winchester but yet standard .30-30 Winchester ammo can be fired in the chamber if need be).
When all is said and done the beauty of the T/C System is that you do not need to restrict yourself to One Barrel or One Caliber / Cartridge to do the jobs you want to do.
Larry