Some complications but re-entry is possible..
Hi.. I'm not a lawyer, but have researched this a fair bit recently as is relevant to me. I welcome any comments from immigration lawyers on anything I've said below.
Ok, from what I've gathered, the answer is:
You are barred from re-entry after voluntary departure, under INA 212(a)(9)(B)(i), IF YOU WERE UNLAWFULLY PRESENT IN THE US FOR MORE THAN 180 DAYS. (Post visa-waiver, that would mean 180 days after the 90 day lawful visit period/ Pre visa-waiver - your case - that would mean 180 days after the expiration of whatever visa you entered the US on before your 2004 departure).
IF YOUR OVERSTAY WAS LESS THAN ONE YEAR, the bar is for 3 years (from the date you departed I think). However, if your overstay was for ONE YEAR OR MORE the bar is for 10 years.
[I'd note that for anyone who voluntarily departed pre-1996, I don't think these rules apply.. see below].
So, you may already be eligible for re-entry, or if not, will have to wait until 2014.
HOWEVER, once eligible, I'd suggest applying for a visa, rather than attempting to use visa waiver. There's a question you'll need to answer on the green entry form about having been excluded and deported, and although you were NOT DEPORTED, I suspect they might consider the 3 or 10 year ban to be considered exclusion (a lawyer will have to confirm this). It's better to discuss that at your local consulate before you buy air tickets rather than having to explain it on arrival at a US port. (Note: Even with a visa, border officers can still refuse entry if they think you're likely to overstay).
If you overstayed LESS THAN 180 DAYS (or voluntarily departed pre-1996) and were therefore not barred, then theoretically, you are eligible for visa waiver, but don't bank on having no complications as border officers seem not to know the law on this and may dispute it (as per my own recent drama). Again, I'd suggest getting a visa so you can deal with any questions in your local consulate.
To be clear though, people in this latter situation were NOT EXCLUDED and theoretically should not state that they were in answer to question (d) on their entry form. I've checked this with a US immigration lawyer. The challenge is to convince border officers of this, because they're now pulling up past processes with the fingerprints, etc. I'm currently seeking to have some kind of letter or annotation to my file, to confirm the law on this matter.
I have some useful references on this stuff that I can't post here yet as this is my first post, but am happy to pass on if anyone's interested.