I have seen many domainers are depending on development and revene for keeping up with the charges. So do you develop your domains, Park them, Do you prefer ecommerce, advertisements like adsense, affiliate programs? or you just forget about the domain name after regging it.

I don't really have so much domains, so I won't forget them. Some of them are for parking, but most of my domains are developed/ in development stage.
A developed site will worth a lot more than just a parked one ( depends on the domain, of course). ;)

I develop. Professionally I am not a domainer I am a web designer. :D

Well I bought some sites on ebay and some sites that I had bought I sold to a friend. Some other sites I let drop as they were losing money not gaining and no sense paying hosting on sites like that. Had owned many domain names like probably 75 or so, but most of them are now expired and were not earning money so I did not renew them. Some domains I renewed a few years trying to see how to make them into sites or to earn revenue from adsense ads type of thing and also from parked domains. Did earn from parked domains but no longer doing that.