Welcome to the site! Sounds like you are on the right track, as there are many options. Here are a few I would suggest in a general (but not necessarily written in stone) order of priority:
First read all stickies on LS1Tech.com -then:
Catback (or true duals if you wish)
LT headers / ORY (or true duals if you wish)
Port throttle body
Other non-power (but still great) mods:
Just a few ideas for you to think about. It really comes down to what you want to accomplish and how much money do you want to spend to do it. The search function works well on this site as most (if not all) of these topics have already been addressed in the past. Good luck!