If you are not sure if you need cleats, then you probably don't need them.

I use cleated shoes because I've been riding and racing for over 40 years and I couldn't imagine not cycling in them. I also take the long way to work, and after work I usually go for a ride that sometimes takes three hours before I get home. If that's what you plan to do, then I would certainly recommend cleated shoes. SPD is the most versatile, IMHO. But if you're just riding to work and back, no hills or rain, you can just go with what you wear at work.

If you do decide to go for the cleated shoes, I would recommend the Shimano RT-82 with SPD cleats; the "RT-" designation is basically a mountain bike shoe without the lugged sole, so you can use them for touring, walking on pavement. I rode P-B-P in my RT-80's, so they're stiff enough & comfortable enough for extended rides.

Luis