Hmm, in the end, it's a tie between my Wii, and PS3. Both of them are really fun, and have their advantages, and disadvantages.
For example: The Wii is a good system for family fun, while the PS3 is for more hardcore mature games, both of which I love. However, the Wii sucks at Internet Capabilities and Graphics, in which the PS3 pwns the Wii at that point.
Once again though, the Wii is just so simple, and easy to use, and it really has powerful first-party games, like Brawl.
In the end, it's an even tie. I would say Xbox 360, but I only play it at my friend's house, and why pay for Live when you can use PSN?