Graphic Bulk Emails - not spam but landing in spam boxes

I'm really frustrated and hoping someone out there who does bulk emailing can help me.

I run a very local coupon site (kind a daily deals/groupon type thing). I email to a huge list of local residents with weekly updates of what kinds of deals they can find on the site.

I understand that a lot of the words like free, coupon, savings etc. are deemed spam by emails companies have have gone out of my way to eliminate them. In fact, if I take the text of my emails and run them through spam assassin I get a score of 0.0.

Now, here's my problem. To get people interested in coming to the site, I want to use graphic emails. I have no problem creating the emails - however, when I try to send, they end up in spam.

Does anybody have any suggestions as to what I can do to get these emails out to my list so they actually land in the inboxes? I've asked people to whitelist, but this is a really big list and most people are lukewarm. They like getting the deals, but it's not a big thing in their routine so they aren't going out of their way to get them - and they don't really miss them if they don't get them. I understand that - if I miss a groupon email I don't really notice.

It's just frustrating to have so many emails not hit the inboxes.

Suggestions anyone?

Tami