I use WeatherBug Elite. "Follow me" is enabled but I only have "use network" enabled and not GPS. Seems to be pretty accurate at following my location, and has not noticeably impacted my battery life. Spare Parts shows only minimal partial wake usage by WeatherBug.
I've tried a number of weather apps, WeatherBug is the one I like the best so far. Keep in mind though, that when I use a weather app it's not so much to tell me what the weather is like at that moment but what the forecast is - so widgets that tell me the current temp and weather are mostly useless to me.
The Weather Channel app/widget is about the most useless one I've used. I hate it.
Clark