How would you feel if you could recall every detail of every achingly painful moment of your life? Sure you could remember the good moments too, but I think we endure more moments in life than exalt in...our bodies and psyches forever scarring over and forgetting the pain and the tedium. (EDIT:...Then again, is it tedium just having an ok day without any memorable jumps for joy or is it cynical to think that if you're not leaping about like a high hippie you're not happy?)
At the same time, maybe we'd learn more from the past if its lessons were immediately available. Perhaps some of our actions would be more cautious, not wanting or needing to repeat old mistakes, but perhaps they'd also more informed and leading to greater breadth of experience.
Also curious would be "memory junkies" who live in the past...those who keep "taking hits" from good old times and those who implode, forever stuck in old nightmares.
Regardless: I'll take a memory chip. I'll just have to learn to use it wisely.