I grew up competing in the "A" circuit Junior Jumpers in California and my first horse big time horse was a tb and my second a Hannoverian. They were both wonderful horses.
My personal opinion is like many of the others...find the best fit for you reguardless of breed.
Second, I really believe that a tb/warmblood cross can be one of the most breathtaking of them all and extremely wel suited for jumping (especially the big fences). The grace of a tb and the power of a warmblood can give you an excelent mover with impulsion, grace, scope, and much more. Likewise, their dispositions seem to work very well together, both complimenting and correcting each other.
Good luck...give us a pic once you find one!