I tend to buy one of everything to give it a try, and I'm not kidding. (Kevin calls me a marketers dream...) Very few things stand the test-of-time and become my favorites:
Toys - Small black Kong, cloth frisbee, the 20cm motivation toy found at The Buddy Company
Leashes - 3 foot black leather or the 3 foot K9 Sportz leash from http://www.k9toolbox.com
My tracking line is made of the K9 Sportz material and it's strong, feels great, is waterproof and the mud flakes right off making it easy to clean.
Favorite collars - For Bullet... his nylon flame collar, 2" leather collar, black leather with grommits, and his "SunBurst Saturn Lighted Collar" from Lion Country Supply. http://www.lcsupply.com/store/flashcart.cfm?section=1552
Mine is yellow and is visible from up to 1/2 a mile away. When my black dog is running through the black night, it looks like fire dancing through the air.
For Ceilidh... fursaver choke chain, thin rolled leather collar.
Clicker - The standard box design, and for some things the Karon Pryor i-Click. Don't like the bone shaped clickers or the larger boxes.
Exercise - The Springer Bike attachment, a must have for biking with your dog. http://www.springerusa.com/
Boots - Muttluks. They stay on better than the cheaper brands, and fit better than neopaws. Expensive though, I plan on making my own in the future. http://www.muttluks.com/
For Puppies - The Kong of course, the Molecule ball, and when the get the hang of that, the Buster Cube.