[WillBellJr]

Brian I own XSI and Carrara and I'd say if you're really looking for a "step up" from Carrara, then Cinema 4D is the best way to go IMO - look around sharbor.com to see if anything fits your budget.

Cinema 4D has a unique and refreshingly simply way of doing things that's a good match when coming from Carrara (as I did as well).

XSI (FND) is less expensive and very powerful, and I can't deny having it in your 3D toolbox is a smart move but it's a complex beast that will take a good amount of time (and training resources) learning and getting used to its quirky ways (using the [s] key for viewport navigation is a good example...)

C4D is just way more friendly as far as learning curve and time to productivity... (The price however is not as friendly unfortunately!)

-Will