DiffMerge is free, try it with AnkhSVN
DiffMerge has a clear interface and supports for file-type specific rule-sets that allow you to decide how to deal with white-space, line-endings, encoding etc.
I’ll be using it instead of my trusty KDiff for a couple of weeks to see how things go.
To use DiffMerge in AnkhSVN head into the Tools > AnkhSVN > Edit the AnkhSVN Configuration menu option and then paste each of the following command-lines into the associated configuration option.
C:\Program Files\SourceGear\DiffMerge\DiffMerge.exe "%base" "%mine" /t1="Base version" /t2="My version"
C:\Program Files\SourceGear\DiffMerge\DiffMerge.exe "%base" "%theirs" "%mine" /r="%merged" /t1="Base version" /t2="Their version" /t3="My version"
Alternatively you might want to check out Trevor Green’s instructions on using DiffMerge with TortoiseSVN if you are not yet sold on AnkhSVN and it’s Visual Studio integration.