I did kind of the opposite....I had a full frame, then I added a crop body. The crop body became my primary body, receiving about 80% of my overall camera usage. This was because of the much greater pixel density (a.k.a. "reach") that the 1.6 crop sensor provided. I did keep the full frame.
Then, about a year and a half ago, I added another crop body, the 1D4. This is now my primary body, even though the pixel density isn't quite as great as the 50D. But it still has pretty decent density (a bit better than the 5D2), and has noise performance much, much greater than that of the 50D.
Although crop bodies are most often better for what I shoot and how I shoot it, I do keep the full frame around for those situations when it may be useful as a backup, or to loan to a friend who doesn't have a DSLR.
"Your" and "you're" are different words with completely different meanings - please use the correct one.
"They're", "their", and "there" are different words with completely different meanings - please use the correct one.
"Fare" and "fair" are different words with completely different meanings - please use the correct one. The proper expression is "moot point", NOT "mute point".