"Living the life" would be me chilling in some sunset destination, port right there. I have nowhere to be and no obligations to fulfill, just enjoying the nice 28 degree weather at some waterside cafe, waiting for the evening to fall. I can hear faint tropical house coming from the beach club in the distance; a fancy dinner and some good company is awaiting me. I can be anywhere I want, whenever I want, and tonight it's right here.

...That's the first image that phrase conjures in my head. "Living the ideal life" is an entirely different question wherein I need to weigh all my real-life responsibilities and circumstances. There's a few things that are essential for me in this ideal: I live in a warm place, I can do my work without feeling any financial pressure to survive, and I am able to move freely from one place to another. In these ideal scenarios I try to not think too hard about family, friends, and lovers, because I know the nomad life I desire sometimes means we will see each other very little.
From what I can gather from other replies, a lot of people's ideal lives are centered around living in a nice place, being part of a community, and being surrounded by arts in some way. I really like that, as if I just got a glimpse of the things most important to the human experience.