They are both fine products. The better rebate is a major plus for the 5500. I have the hc 6500, but almost bought the 5500. What changed my mind was the drop in price to under 2k. Rebate or not, you are getting a very nice projector for that price. You should read Art's review at www.projectorreviews.com
He sure liked the 6500 better and I think thats when the retail of it wasn't nearly as low as now. On a side note, Ive seen the panny 3000 in action at a local dealer and the hc 6500 on the opposite wall. The black levels look comparable to each other with a slight edge I must say to the 3000, but the sharpness on the mitsubishi was ALOT crisper than the panasonic 3000. Plus it looked brighter with both being calibrated to optimal movie viewing settings. That with the price made my mind up right there. Personally I think you are getting all the benifits of an lcd projector with the color accuracy of a good dlp. I love mine.