When I went with digital, I knew that I wanted Canon 20D's, as it was a great camera for the price range. But I would have to use a kit-lens, as I couldn't afford good lenses. So I set up a plan, it's a long term plan, but it's working out so far.
I first bought one 350D and a Tamron 28-75/2.8 and was fortunate enough to get hold of two great L lenses used, that has gotten me some work. Then I bought a second body (as it's important to have a backup if you shoot weddings, like I do). Now I'm working on getting better glass than the ones I have. When I have the glass I want/need, then it's time for upgrading the bodies, to whatever model will fit me at that time. And I epxect that will happen sometime next year about this time.
So my advice is: if you're serious about your photography, either you want to do it just as a hobby or as a mean of income, make a plan. Spend your money wisely. To me it is glass that is what I want first, as good lenses will last 10-15 years without having to replace them, while camera bodies, especially with the fast paced technology today, will change each year with something better, faster, cleaner, etc.