Identical twins are basically "clones", as their DNA is as identical as two clones' would be. As you most likely know, twins don't act exactly alike.

Genes don't define everything about someone--environment and circumstances also play a very significant role in shaping one's personality. While it could be hypothesized (but never perfectly proven) that two clones or identical twins, living under the EXACT same conditions, would turn out exactly alike personality-wise, this is practically never the case, and therefore there will always be differences, sometimes stark ones.
Source(s):
http://www.thetech.org/genetics/ask.php?id=147 (this regards cloning other creatures besides humans, but the fundamental concepts are the same)

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Genetically there is no real difference between twins and clones. Except that clones can be born further apart. Twins obviously manifest distinct personalities, even under the same conditions, more-so if they are raised separately. A clone would be even more likely to be raised in different circumstances than the original, and would thus have more opportunity to develop a different personality.
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We have already made clones, and they do not have the same personalities. Personality is determined by external factors, such as experiences and environment.

http://www.frontierchannel.com/gallery/albums/images/cc-mediapix14.jpg
Source(s):
http://www.thetech.org/genetics/ask.php?id=147

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I think environment would have some effects on my clone. We wouldn't be exactly the same, but genes would dictate that we would be extremely similar.
I have twin cousins who live in different states. Last Christmas they showed up (separately) with the exact same outfit on....totally unplanned. It's amazing how alike they are. I imagine clones would be the same.
Source(s):
Interesting article on twins raised apart and how alike they are:
http://science.howstuffworks.com/genetic-science/twin1.htm

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I would probably destroy my clone. I have a very strong personality and very opinionated and he would always be wrong

http://www.youtube.com/watch?v=YSQPnaOHPWg
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It would act exactly like me up until we start to experience different things. That is, RIGHT after cloning, you can ask us any questions or put us under any controlled condition and we'd yield identical test results. HOWEVER, the longer we exist seperately, the more different we become (alas, the power of nurture) and hence in a year's time we'd be somewhat different. In a decade we'd have no more similarities than identical twins. In 50 years we can differ extremely drastically: I mean, one of us would probably be dead while the other is not. How much more different can you get?
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as drmatt and others have stated above, personality and behavior are the results of a combination of genetics and environment. chn-cs-htg above raises good points in theory as well in that clones created at the same time in the same place would remain identical until they began to experience different stimuli from their respective environments.

from that point on, the analogy of "the butterfly effect" taken from the study of non-linear dynamical systems takes over. minor differences in initial conditions in can soon cause greatly different behaviors of similarly constructed non-linear systems. and the most extreme example for this question is shown above - one dead, one not.
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It entirely depends if they had the same life as you as well. Genetic markup does help shape a persons personality but it is not a defining factor. All that is copied is DNA, not memories. So, if they were merely brought into this world as a genetic copy of you and didn't live your exact life they would be a different person, even if slightly similar in some overall traits. The link below is a good quick read.
Source(s):
http://www.thetech.org/genetics/ask.php?id=147

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It would be different. Sure, you may have the same tenancies that you have [ex: being more aggressive], or sometimes even the same facial expressions and gestures, but the fact of the matter is that a person cannot be defined by their root atributes.. or can they? That's really a question you should ask.

I think that if we look at any person, we can see one trait that will stand out. Often times it is that trait that defines them, also, it's something that has probably been in them since they started interacting with people other than mom and dad.
If we define every person as we do animals, like a litter of puppies - some seem shy, others friendly, etc. Then yes, then you can say that you and your clone are going to be the same.

But to limit one person to a single attribute is like having one jelly bean from the bag and assuming it's all sweet.
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A clone, a genetically identical individual, would certainly act differently from it's template for the same reason that twins do not always act the same. Behavior is determined by a complex interplay between genetics and environment(nature vs. nurture), so even two genetically identical people will become different as they interact with and are shaped by different environments.
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I would never hang out with my clone. We'd fight a lot. I'd probably do horrible things my clone.

I think a lot of who I am is based on how I grew up, so I don't think my clone would behave anything like me if he had a different experience.
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I think the answer to your question is related to this one:
If it was possible to reverse time and bring the world (I mean EVERYTING) back to exactly how it was 24 hours ago, do you think you would act exactly the same way you did for the next 24 hours (just like a movie, if you rewind back and play it again, the same things will happen a second time)?

If not, I think the answer to your question is no. Because it would mean that genes + environment are not enough to define exactly someone's personality
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