I really liked the finale. I've been a "fan" of Lost since the beginning. There were definitely times when all the twists, turns and answers that turned into more questions really irked me, but I couldn't help watching just one more episode (and then another...). For me the series mirrored humanities fascination with trying to solve life's mysteries with science, philosophy, religion or brute force, but in the end, it all comes down to "why am I here?", which is still the greatest mystery of all.
Lost answered this question through Jack's dad - "Nobody does it alone, Jack. You needed all of them and they needed you." That's still an answer that leads to more questions, but I can live with that.
Other post-Lost musings @ The LOST Recap and Making sense of LOST.