To answer the questions specifically:

[quote:23iq9mqj]I read yesterday, in one of the forums that God is going to hold us accountable for each sin we commit. That we would have to continue to repent for these sins even when we die. How is that?[/quote:23iq9mqj]
This is incorrect as regards sins that have been absolved in confession. While we do need to make restitution through temporal punishment, there is no guilt to repent of after we are absolved.

[quote:23iq9mqj]I guess my question is, is our sin wiped away when we confess them? Do we start from that point on a clean slate, so to speak?[/quote:23iq9mqj]
Yes. You are absolved of your sins. As far as the east is from the west, so has God removed you from your sins.

[quote:23iq9mqj]And do we have to actually say outloud to the priest every sin we want to be forgiven for, or can a person be vague[/quote:23iq9mqj]
You must confess any and all mortal sins that you can remember.

[quote:23iq9mqj]Another way to say that I guess would be, can we keep certain sins only in our hearts, between God and us? and still be forgiven?[/quote:23iq9mqj]
Does that sound like [i:23iq9mqj]confession [/i:23iq9mqj]to you? Me neither. If you intentionally withhold confessing a sin, you are certainly not absolved of it, and you may have sinned or even invalidated your confession in doing so.

If you honestly forget, you are forgiven. However, you are obligated to confess the sin the next time you are at confession.