@BlueChicken,
This is a subject I would willingly discuss all night with a group of insightful friends and a copious amount of hop-laden refreshment. Since we are talking about nebulous concepts like "what it is to be human," potential/experimental technologies, desirable augmentations to existing human qualities, and consequences (from predictable to completely unforeseen), any discussion is going to be largely speculative. That said, I will attempt to summarize my thoughts into a succinct nutshell:
(1) The notion of human progress, as regards humans themselves, is largely a myth. In all important respects, what defines us as human has not changed since the time of Sumeria (or earlier). We exhibit the same emotions; the same tendencies to form tribes, base-pairs, societies, and laws; the same urge to explore and conquer our surroundings.
(2) Those quantifiable elements that we would include in any common definition of "progress," including those expressed in modern human physiology (gains in height, increases in lifespan), are directly or proximately attributable to technology.
(3) The "evolution" of technology is quickening, at an apparently exponential rate, and will probably continue in its rapidity unless some event occurs which is significant enough to wipe out the entire process.
(4) If the rate of technological evolution continues unabated, we will undoubtedly approach a point where what we have traditionally held to be "human," as fuzzy or subjective as the term may be, will be drastically altered in meaning and expression. This may be negligible to us, in the case that our perception shifts in proportion and pace to the actual changes occurring, or it may manifest in the manner of a systemic shock to human civilization at large. My bet is on the former. We are witnessing amazing vicissitude in human communication right now -- how many are positing that the internet and text messaging have fundamentally changed what it means "to be human?"
That is my thought on the state of impending transhumanism at its most base level. We could get into the finer points of "heap" logic -- i.e. at what point does change constitute a human becoming something else? Ray Kurzweil discusses this subject at great length in his books
The Age of Spiritual Machines and
The Singularity is Near.
As for my opinion on whether transhumanism is good or bad, I would say neither. It is what it is -- inevitable change, mutability, adaptation, advancement.
Every change invites unintended consequences and unforeseen reactions, but there is no longer an option to go back to the way things were. Ludditism has a certain romantic appeal to it, but does not provide a practical solution for the problems of our age, nor does it mesh with our natural tendency to explore, invent, meddle.
The idea that each generation of humans is subsequently degrading in quality (morally or otherwise) has been espoused for thousands of years. Indeed, my own observation often seems to strengthen this familiar denouncement. Still, such judgments are matters of perspective. Contrarily, the benefits gained through our improving technology are quantifiable.