When you're packing your gym bag and picking out what you're going to wear, choose your shoes wisely. I'm not saying they need to match your clothes, but they should match your workout. There are so many different athletic shoes to choose from nowadays, it can be confusing as to which may fit you and your needs best. Here are a few different styles and their pros and cons.
Running: These seem to be the most popular gym shoe, although they should probably be the least popular. Running shoes are built for comfort, which is understandable as they’re meant to handle lots of impact and soften the blow while running. The soft cushy soles lack stability and are generally a bad idea for lower body exercises as your risk of rolling an ankle increases in these. This includes the running shoes that are built for stability. They are great for running, and I'll even wear them during an upper body workout, but you need a solid surface to push through for lower body training.
Skate (or basically anything with a flat sole): This is the shoe that I think most people should be using in the gym. These shoes are flat, generally a bit wider, and have little cushioning. This means that you're pushing into a solid surface and are able to reduce or increase pressure in certain areas of your foot, affecting muscle recruitment. I especially prefer this type of shoe when training my posterior chain, especially if it's heavy. Although these are great shoes to lift in, they certainly aren't great for running, which may make them less than ideal for conditioning or circuit training depending on what movements you’re doing.
Weightlifting: The name says it all. These are for moving weight. The elevated heel in these shoes decreases the need for ankle dorsiflexion, making it easier to get your knees over your toes and deep into a squat, and the stiff soles with little cushioning are great for handling significant amounts of weight. These are ideal for Olympic lifting, and great for just about all other types as well, the only thing I may not use them for is posterior chain exercises (hamstring and glute). A great shoe for weightlifting, but if you want to try running in these, good luck to you!
Training/Metcon/Crossfit: These are more of a hybrid of the three shoes you see above. If I were to buy only one shoe to workout in, this would be it. These generally have a slightly elevated heel, wide foot bed, a little cushioning, and a solid sole. While these shoes may not excel in any one area, they seem to handle everything fairly well and I actually prefer them for some exercises such as low bar back squats. This is a great all around shoe that is gaining popularity, and with good reason.
If you plan on doing a lot of a certain form of exercise, I would highly recommend getting a shoe that fits the activity. If you're planning on doing a little of everything, the training shoe is probably your best option. Over time you can add to your collection and choose the best shoe for the workout.