IMHO the only way to handle a film version of an old TV show is the way the first Brady Bunch movie was made. It was evocative of the series to a fault, but irreverant and ironic at the same time. I actually loved the way they handled it - they honoured the original series, but did some really weird, sublime things like having Alice on screen in an S&M costume for a fraction of a second to make you laugh, and I think it worked.

There really is nothing to be gained from making a film based on a TV series unless they try and look at the source material in a different way while remaining "true" to the spirit of it, rather than making a 120 minute episode with the hottest actors de jour.