With the need to use a Google account with Google Wave, you'll want to be careful if you receive the Google Wave invite and you're logged in to a Google Gmail account which is NOT the one you want with your Google Wave account.
Why you ask?
It may just happen your Google Wave invite is sent to a Google Gmail account which is NOT the one you'd like to share with persons with whom you'll be using Google Wave with.
If the Google Wave invite happens to come a Google Gmail account you do not want to use, you can forward the Google Wave invite email a Google Gmail account you do want to be used as your Google Wave account.
Important Note: Be sure the first time you use your Google Wave invite URL you are already logged in to the Google Account which you want to use with Google Wave. You only get once chance to use the Google Wave invite, if you the use the Google Wave invite URL and then you try to change to a different Google account, you will lose access to your invite.