Here are some great utilities for Unreal editing, thought I don't use hardly any of them...

Wally skin creator: http://www.telefragged.com/wally/
UnrealTorment all around tool for UT: http://www.planetunreal.com/unrealtorment/download.html
ModPlug
    - The player let's you listen to .UMX files without UT or UED being used
    - The tracker lets you convert regular music files to .UMX files for use in maps
    - URL: http://www.modplug.com/modplug/download.php3
UT Toolkit - used for converting .t3d (Unreal Brush) files to their respective DATA and ANIV files to be used as decorations in UT: http://v2.gerke-preussner.de/standalone.php?envCnt=work_games_uttools_uttoolkit

Does the same thing as UT Toolkit, but is much more simplified: http://www.planetunreal.com/screen/meshmaker/

Tarquin's brushbuilder used for creating odd shapes and the like in UnrealEd: http://www.planetunreal.com/tarquin/

Toolbar Creator - let's you create a custom toolbar in UnrealEd which can come in quite handy: http://www.planetunreal.com/fordy/tbarcreator.htm

WOTgreal Exporter (the only tool on this list that I have actually used and still use every day..oh yeah, and I've used meshmaker) - This tool decompiles UT class packages (*.U files) into readable files: http://www.unrealwiki.com/wiki/WOTgreal

there are more tools out there, these just looked like the best to me....