If you want easy going, loyal, always ready to play but generally not overbearing, go with a golden retriever. I was just thinking about my Sadie, it's been 5 months since she left us. She was always there when she was needed, and took so much shit over the years. All she ever wanted was to be loved and chase down a tennis ball, and most of all make sure her family was safe. Gentle as can be.
Only drawbacks are the hair... yeah, it gets everywhere.
Thing to keep in mind, with any dog, you have to put in the effort, spend time with it, train it, teach it, exercise with it, and develop a relationship with it. Only then will you not be stuck in the typical failure of "Gah! I hate this dog!" or just outright neglect.
If you're so inclined, go to your local shelter and find one to love. There'll be purebreds, but there'll also be mutts. For a first-timer, I'd go with a young shelter dog (mutt) or something easy like a lab or retriever. If you actually intend on devoting time to your dog, then I might go as far as recommending some higher maintainence breeds. If you aren't going to be there for the bulk of the day (work or whatnot), then stick with my original recommendations, otherwise you'll probably regret it later.
Adding a couple comments to various recommendations:
- Boxer : Yeah, hyper, requires a LOT of attention and exercise. Despite they're playful demeanor, they're actually very intelligent dogs, which can get them into a lot of trouble.
- Doberman : Very protective, NOT very agressive - don't confuse the two. They're loyal to their owner especially if you take the time to bond. Unfortunately, they're also very powerful and headstrong dogs which make them harder to handle. They also require a LOT of attention.
- Huskies : Very loyal dogs, but also the outdoorsman of the species. They require insane amounts of attention otherwise tend to be rather destructive. They also require copious amounts of exercise.
- Greyhound : They need EXTREME amounts of exercise. I'm not kidding... you better have a huge yard that's fenced, because they love to run (duh). Rescue Greyhounds also need special care. Sometimes they will have joint issues and definitely will have behavioral issues from neglect.
Each will also come with their own set of potential health issues as well. For example, Golden's are (as I learned the painful way) prone to pancreatic cancer. Greyhounds, as mentioned are prone to joint issues. Dobermans get bloat easily. I forget what's common with boxers, other than occasional infections in the eyes.