I agree with all the previous comments and I have a few to add:
If you don’t already have a good set of pans, invest in a commercial set like Magic Line or Fat Daddio’s.
I love my Ateco turntable with the cast-iron base but Wilton makes a similar one. There is no comparison in my opinion between the cast iron and the plastic ones. Free shipping on this one:
http://www.amazon.com/Ateco-612-Revolving-Cake-Stand/dp/B000BVFYUO/ref=sr_1_1?ie=UTF8&qid=1334063682&sr=8-1
The printer will be invaluable to you if especially if a client orders several dozen zebra-striped or paisley toppers. Believe me, I’ve hand-painted them and now that I have the printer everything looks so much more professional and takes a fraction of the time.
An airbrush is another purchase you might want to consider. I don’t use mine much but there are certain projects that can’t be done without it.
By far, the most invaluable item I own is my Agbay leveler. I purchased it a couple of months ago and it’s saved so much time and energy, not to mention it makes perfectly level cuts. I bought the Deluxe which has two blades so each cake is leveled and torted with one cut. It’s really expensive but, if it makes you feel any better, it’s a company owned by a former cake designer and she includes a little hand-written thank you note in the box! I don’t know if I would’ve bought it starting out if I’d known about it but if you do have an extra $300 or so lying around it’s the best investment you’ll ever make for the sake of your time management, your end result and your sanity.
http://www.agbayproducts.com/
