My running gear selection has evolved over time as I've gone from beginner to advanced, recovering, and somewhat back to beginner again.
For Nipple Protection
Nexcare Bandages. Best results if applied about an hour or so before, so that they'll set prior to running. Remove immediately after running for easy removal. Small sizes are good for shorter distances, but larger sizes for 20 miles or longer. Apply to dry skin only and allow to adhere well before striking out.
Workhorse trainer for cushioning: Saucony Ride 10 - I've been using the Rides for almost 10 years now. They're not quite as good for me personally as the 2007 pairs, but they're still the best fit. I've had 15+ pairs of Saucony Rides overall -- usually used to 450-500 miles, but a 75%+ of those miles are on the treadmill. It is pretty much the most indispensible piece of running gear I have.
Speed/Tempo/Race Shoe: Mizuno Wave Rider These seem hold up to high mileage much better than the Sauconys. My first shoe I purchased for running was the Wave Rider 9, and I went through 4 pair of them. I skipped the Wave Rider 10, but came back to them for the 11s and 12s. Then, I had occasional black toe issues with the Wave Rider 9 model in a size 10.5, normal width. I switched to size 10 width EE for the 11s and 12s. A much better fit. The cushioning on these shoes is less soft than the Saucony, so you start to feel the road a little bit more at the end of the marathon, but the lighter feel to them makes it worth it to me.
Sole F80 (2009 model) - lately I've replaced the rear roller a few times, but the treadmill has been through 3 moves, including one of 600 miles. It also seems that I probably overtightened the belt due to be being confused about which part was loose (it was the drive belt, not the running surface belt).
I upgraded to the Garmin 220 from the Garmin 305, after I temporarily lost the latter. The Garmin 305 fell apart on a run. I managed to have the manufacturer replace it for $75. I've already had to replace the Garmin 220 as well, but after only a little over two years. I'm beginning to eye the Apple Watch and/or just using RunKeeper.