The downhill spiral started when Dave Thomas died. After he couldn't be in the ads anymore they had some really awful marketing. They tried Mr. Wendy, who was, to me, a blatant rip-off of Joe Isuzu, only not effective or funny. Then they had the guys wearing bright red braided pigtails. These campaigns were dumb and certainly didn't get me to eat at Wendy's. There was also that incident where a woman found a finger in her chili, which drove me away for a while (I used to eat Wendy's chili all the time). Wendy's even canned the Biggie name, which was, well, what made Wendy's Wendy's.
I can't eat fried food so I rely on good grilled chicken sandwiches (minus mayo), baked potatoes, salads, and chili at fast food restaurants. Wendy's had been my number one choice but I too have noticed the overall quality sliding. I switched alliances to Panera Bread a few years ago (both for the non-greasy food and because a lot of my friends got jobs there) and haven't been to a Wendy's in some time, but I hear it's not getting any better...