Sometimes people ask me for my advice on technology. What kind of computer to get, should they get a tablet, what smartphone is the best, etc. As I have tried to answer both honestly and personally (I don't recommend the same thing every time) I have found that it all comes down to ecosystems. While most gadgets will interact with most other ecosystems, they work the best (and with the fewest headaches) when they're in their own.
For example, when you buy an iPhone, you're not just buying a phone, you are taking a step into the Apple ecosystem. iTunes will be used to move music and applications onto and off of your phone. You will be able to purchase music and TV shows and movies through iTunes. Is that what you want? I was recently asked about whether a couple should get iPhones or Android phones. I asked, "Do you own any Apple products?" They owned a couple of iPods. Then I asked, "Do you like the iTunes environment?" They said they were fine with it. Based on that, I recommended iPhones. They had already bought into the Apple ecosystem and liked it. The iPhone would just be an extension of that. In addition, an iPad is a further extension as is the Apple TV, etc.
Another possible route is with Android. Google has also built an ecosystem around their Android phones. They have music, movies, and apps available for purchase. They work great with gmail and other Google services. If you enjoy the Google environment, you should be buying Android smartphones - they will fit in the best. However, as a caution, the interface with an Android phone varies from phone to phone. If you are getting an Android phone for yourself and a significant other (a spouse for example) and you'll be swapping phones every now and then - my wife will grab my phone when she doesn't have hers on her and visa versa, make sure you get the same phone so you will have the same look and feel. It will save you a lot of headaches (I recommend a Nexus phone in that case as it always has the default look and feel). There are also a lot of tablet options as well but I would probably recommend the Nexus 7 tablet or maybe something by Samsung or Asus.
The route that I took was with Windows Phone. As with the others, there is a ecosystem that I bought into. Windows Phone is deeply integrated with Microsoft Office (Word, Excel, PowerPoint, Notes, etc.) which is great. It also has a service called SkyDrive that allows you to synchronize your files among various computers and the cloud. This means that I can create a document on my desktop, update it on my Windows Phone, and then print it from my laptop without going through any extra steps (after SkyDrive is set up). It also integrates with Hotmail (soon to be Outlook.com) and Microsoft's online Word, Excel, Notes, and PowerPoint applications. As far as tablets, there really isn't one for Windows yet but the Surface is coming this October and looks to be a great tablet that really complements the Windows ecosystem.
All of these routes have positives and negatives. Usually I recommend that if you've already bought into one, continue on. If not, you need to weigh the pros and cons based on how you will use technology. Don't just "follow the crowd" find what works for you and go with that.