Matt: I like these because of the range of weight you have and how little space they take up.
Bowflex SelectTech 552 Dumbbells
Matt: Kettlebells are extremely useful in workouts. They allow you to create patterns of stablity and instablity. I'd recommend buying 12kgs, 18kgs, and 24kgs. You can buy sets or singles it depends what you're looking to do.
Powder Coat Kettlebells
Matt: Useful for warm up exercises or making sure the right muscles are working during more complex movements.
First Place Mini Band
Matt: Best treadmill because of the low impact on the knees. There still is impact but its less than other companies.
4Front - Commercial Fitness Treadmill | Woodway
Matt: This is an olympic bar. I'd recommend the full set so you can preform the widest variety of lifts.