Clean Pet w/metastatic disease - should treatment be continued?

First time posting, so may botch this up. Diagnosed w/Stage IV NSCL in April '11. No lung tumor found, but malignant pleural effusion and spread to lymphs. Went on cisplat/alimpta/avastin - sick as a dog for 2 cycles. Switched cis to carbo - sick a lot less and have been doing that since. For the effusion, had to get the fluid tapped a few times last year and the doc suggested surgery. Was gung ho, then changed my mind at the last minute - good thing apparently as the lung cleared up on its own. Haven't had fluid since September. Had a clear CAT in January and just got a negative PET last week. Asked the doc what next steps were and he's not sure as he's had no experience with this. Kind of cool, frankly, to stump your doctor, but also kind of scary as I was hoping for some guidance. Has anyone experienced clean scans with my dx (oh and I developed a DVT and was on blood thinners for a few months as well, but stopped the injections in January with the clean CAT)? If so, did you stop treatment or continue?
Truthfully, I feel great now - have worked throughout and my attitude (past the first awful shock filled couple weeks, of course!) has been that this isn't the end by a long shot. While a big part of me wants to stop as I'm not sure how many good cells I'm harming trying to keep away the bad, a small part has the "if it ain't broke, don't fix it" mentality. Would appreciate any insight on others with similar experiences or books to read, sites to visit, etc.
Thanks!