I’ll start off the hitlist with my current tool of the moment. I’ve used Araxis Merge on trial a number of times in the last couple of years but never QUITE needed it enough to pay the £94 for the basic edition. I tried WinMerge a while ago, but it was flakey as hell. It’s spot-on now, and works really nicely with CVS. Having just started some serious team development with CVS for the first time in ages it is so totally necessary.