Sorry about digging the grave, but I was wondering if the carat weight people talked about here were total carat weight?
I saw a few TPFers talked about seeing most of the women in big city burb sporting 2.5 carat e-ring (when people say that, I assume the center stone is 2.5 ct)....
When this thread was originally written, the OP stated that she meant the carat weight of the center stone only...
I personally feel like it's all about what your FH is comfortable with spending... It's also a mix of regional and cultural.
Personally, the ering was "my thing" - I would rather have a larger ering and spend less on a wedding dress. Therefore, I got a 2.4 ct center stone and spent only $1k on my dress. Conversely, I have friends that valued their weddings and dresses more. One friend is not really a "jewelry person," so she was perfectly happy with a 1-ish carat and wore a $12k dress in a $90k wedding! Another girl wanted "at least a 2.5 carat" solitaire, but RENTED her dress for about $60 and got married at the courthouse!
It's all about preferences and what you're comfortable spending on each aspect. Different strokes, ya know?!
As to the OP's original question... I think the true average size is about 0.4-1 carat - the quality, however, is all over the board!