I'm not a big fan of the thin lycra stuff, but that's mainly because I'm a bit self-conscious and don't like the feeling of something quite that form fitting. I usually wear workout leggings instead, since the material tends to be a bit thicker, with a baggy tank top or t-shirt of some sort. I'm not a serious enough cyclist that what I wear makes much of a difference to my ride, so I mainly just aim for comfort.
I used to know someone who always went mountain biking in a pair of jeans with a tucked in button up shirt and a big belt buckle and cowboy type boots and I always thought that he must be sooo uncomfortable.