Ah...If you mean Canon, the 5D has been out a long time. You can see a review of it here:
http://www.dpreview.com/reviews/specs/Canon/Hopefully this doesn't sound wrong, but...
As far as which body someone else thinks
you should get, I really feel it's something you should decide due to your needs, and not the opinions of others.
With that said, considerations should include having lenses that would make use of a full frame body, and/or higher resolution sensor?
If you've purchased several EF-S lenses, they're not compatible with a 5D, and will need replacing.
Do you have Canon L glass, or using lower priced lenses which aren't giving you the results your wanting? A new body isn't going to help.
Do you require higher frames per second than the 450D would give, and is size & body weight something that might persuade you?
Read the reviews, consider your glass and decide. They're all good bodies which will give nice results if used properly.
Lenses are your biggest investment anyway... bodies are outdated in a couple of years.