Hi TerryTen,
It is not standard to repeatedly send email to addresses that are invalid or do not want email from you.
Any addresses that 5xx bounce should be removed from your list.
Any emails that want to unsubscribe should be removed from your list.
Emails that were only added becuase you collected a business card or saw an email on a web page (their web site, blog, linkedin, etc) should be removed from your list.
It is OK and normal for some of them to return out of office and other vacation flavored auto responses.
Do you have any test addresses with Gmail, Yahoo, Hotmail, and/or other email services on your list?
Did you see our responses to your previous questions?
http://www.emailquestions.com/email-discussions/6543-email-sending-service.html
http://www.emailquestions.com/email-discussions/7313-like-mail-chimp-but-no-subscribers.html
You may be able to tell if more of your email is going to spam by monitoring how the email is treated in your test/monitoring accounts, and by monitoring your open and action rates.
What is your sending IP?
Are you the only one sending from it? (shared vs dedicated)
Is it monitored for abuse? Are you on any major ISP abuse feedback loops?
Are you on any blacklists? Have you done an IP reputation check?