MygcWaiter,
I believe that you got it all wrong.
The whole purpose of I-94 forms is to track departure of non-immigrants. Therefore, when you leave the country, you must surrender your I-94 to an immigration official or to an airline employee (the airline will forward all collected I-94's to INS). While you are in the country, your I-94 indicates your current status and its duration (if applicable). If the duration is set (say, for H-1 visas), you must leave the country before the indicated date (given that no other circumstances would allow you to stay legally), otherwise you will be deemed out-of-status and any further presence in the country will be counted towards illegal stay. That is why it is very important to surrender I-94 on departure, otherwise it might be very hard or simply impossible to prove that you have left the country before the authorized stay period has ended.
Now, to the multiple I-94's issue. Entering the country, you get your first I-94. However, different filings with INS may result in additional I-94's, which effectively become current making all previous ones obsolete. Such filings include, but not limited to change of non-immigrant status, amendment (company name change or merger) and extension of status. While all previous I-94's are useless, indeed, it is recommended to surrender them all (keeping copies, as noted earlier in this thread, should a need to prove your legal status arise, they would provide ample evidence). Returning from the trip and entering the country, you must fill out a completely new I-94 form and submit it to the immigration officer at POE for stamping. The same thing goes for Advance Paroles as well.
Hope this little essay clarifies the issue a little bit.