Definately get yourself into nitro. it's loud,dirty and a buttload of fun.
I know you are thinking RTR, but also give thought to a buggy kit.
I ran a hyper 8.5 RTR for about a year,it was an awesome buggy but i moved up to an o'donnell Zo1b team buggy kit.building a nitro buggy from scratch was a good learning experience and now i can tear my buggy down,fix it, service it and re-build it with no hassles because having built it,i know what goes where,what looks worn,and if anything is broken or missing.
I know pro kits are dearer, but what you can learn from building them is priceless.
Gaz.(australia)