It really just depends on what you are looking to get out of it in my opinion.
I currently use an xbox 360, but I also still have a PS2 hooked up as well. I never bothered with the PS3, because I honestly wasn't that impressed with PS3 in comparison to what xbox offered in terms of games. Sure, Sony has the rights to some pretty awesome games, like God of War, but it didn't justify the much higher price tag simply for adding a blu-ray player (which are cheap now). The next xbox console is due out in the next 2-3 years and it will also move to blu-ray to allow for discs to store more content and in turn higher end graphics, but don't expect to see the xbox 360 phased out anytime soon....
Remember when I said I still have a PS2 hooked up? It's because the PS2 still has GREAT games and believe it or not, they are still releasing new games for the PS2. Sony never stopped because the reception to the PS3 was less than stellar, and they knew they could keep making cash off releasing certain games ported to PS2, such as Madden and the NBA 2K series. Granted, that is nearly at an end, but still, thats a long run for a game console. The PS2 is one of the best ever in my opinion, and I go back to the days of the Atari 2600 and the NES.
If you like games that are more affordable, with a ton of replay value, and you have kids, then Nintendo is for you. They set the standard for what Microsoft and Sony are doing today in many ways. However, they always did it with the attitude that even if their hardware wasn't as high end as the other guys, they could make a product that related to it's audience better and thus allowed them to compete and constantly stay relevant in the industry. The Wii may not be as cool as the Kinect for Xbox in terms of technology, but remember that it also came out over 5 years ago. Heck, Nintendo had already foreseen and was in the business of "motion controlled" gaming back in the late 1980's.
It's hard to really go wrong, as all of the major systems have their good points and bad points. it just depends on what you are looking for. They all can stream NETFLIX, and all offer you various ways to spend lots of money of stuff you'd swear you'd never spend it on. Happy hunting!