I'm looking for an addon that can give me the range of everybody in a raid at one time, or just the people that are within casting range. I need something to monitor the whole raid, I use to use X-Perl raid unit frames, and they had a built-in range checker, but it use to give me horrid system lag...no idea why.
So anything anybody would mind sharing would rock.

Grid is popular and is able to do range checking. PerfectRaid will also do the same thing. PitBull has raid frames that also range check. These are just a few off the top of my head but I believe most raid frames support this now -- just try a few of them out and see what you like the best :)

I really wanted something standalone, I guess I should have said that, I have tried Grid, didn't like it, PitBull didn't have half the features I am use to using. being a raid healer, changing up my UI all the time isn't so good for efficiency and reaction times