based on everyone's experiences, what are my best next options?
You have several options to consider before surgery.
First of all, you should definitely get tested for allergies (by an allergist, not an ENT) and should get on some kind of treatment regimen if you have positive allergy tests.
Second, you should buy a SinusRinse bottle and start irrigating your sinuses daily (they're available at any national drugstore chain). I'm not sure if your ENT mentioned this to you already but, if he didn't, you might want to consider seeing a second ENT. Saline irrigation is one of the best, easiest and cheapest things to do and most ENTs strongly recommend it to their patients who are dealing with chronic sinus problems.
Third, you should probably be on a daily nasal steroid spray like Flonase or Rhinocort. This will help shrink the inflammation in your sinuses and help them to drain (again, this is one of the first things most ENTs recommend, so if your doctor didn't you might get a second opinion).
Fourth, you might consider getting evaluated for acid reflux. Acid reflux can cause, or aggravate sinus symptoms for some people.
Finally, you should ask about a course of oral steroids. They're stronger than the sprays and can help shrink the swelling in your sinuses so that things begin to function normally again.
The biggest challenge in your situation is giving your sinuses a chance to begin functioning normally again, all of these things will help that to happen. I realize you may not have put all of the details of what your doctor has recommended in your post, but if the only treatment you've had is 3 rounds of antibiotics and 3 CT scans there is no way you should be considering surgery, you need to find a doctor who can help you exhaust all of the medical options before he recommends surgery.