I was just going through on StarWars.com and watching some of the teasers/trailers for the movies, and it got me to thinking - what did you first think when you saw the first trailers for the movies? I was watching the very first TPM trailer, and it reminded me of that time. Honestly, I wasn't on the internet much really, and it wasn't a situation where I knew the exact date when the trailer would be released and all of that like we do now. I knew Star Wars was coming, but didn't know a lot of specifics about it. I remember seeing another movie with my wife (then fiancee), and seeing that Lucasfilm logo come up. Although years later, TPM might be lower on my list of favorite Star Wars movie, I can honestly say I was pretty pumped at that point - and that's when I really started getting back into collecting.
For AOTC and ROTS, the same was true. Each trailer got me more and more excited, and I liked every second of them. I remember from the AOTC trailer "we decided to come and rescue you" and Obi-Wan's line "Good job", and thinking - that's the Han Solo-type humor we were missing from the PT. With AOTC, and ROTS, I was online in full force, and knew so much of what was on the way, but I've always enjoyed movie trailers and they were great. Nothing quite like those first TPM trailers/spots where "Star Wars is coming back" though.
This can also apply to the OT, although I don't really remember the original trailers from back then. I do remember seeing the Special Edition trailers though for the re-releases, and being quite excited. I think I might vaguely remember commercials for ROTJ as well, but I was too young at the release of ANH (Star Wars) or TESB.