Here is some tools you definitely need and some mods doesn't work if these tools aren't installed.
Toolshttp://www.gamesas.com/index.php?/topic/1233101-rel-boss-better-oblivion-sorting-software/ - You must use BOSS, because some mods will have a CTD if they were active
http://www.gamesas.com/index.php?/topic/1246061-relz-wrye-bash/ - Also a must have tool
http://tesnexus.com/downloads/file.php?id=11536 - Recommended but necessary with mod cleaning and troubleshooting (mod issues and conflicts)
http://tesnexus.com/downloads/file.php?id=15781 - Definitely needed, because some mods mostly graphical will sometimes have a CTD if TES4LODGen (similar to the Distant Land Wizard in MGE) isn't used before playing the game
ModsEmma - http://lovkullen.net/Emma/Vilja.htm and her http://lovkullen.net/Emma/oblivionbyemma.htm (scroll down to Houses) mods with http://download.fliggerty.com/download-122 mods
The Nice One - http://www.gamesas.com/index.php?/topic/1247910-relz-map-marker-overhaul/, http://www.gamesas.com/index.php?/topic/1158730-relz-dynamic-map/, http://www.gamesas.com/index.php?/topic/1211390-relz-enhanced-economy/
http://tesnexus.com/downloads/file.php?id=27710 (latest http://www.gamesas.com/index.php?/topic/1229692-betaunofficial-oblivion-patch-uop-v340/)
If you're looking for mods just use Yacoby's http://www.tessearch.com/ and http://www.tesnexus.com/index.php has the most popular mods for http://tescosi.com/wiki/Main_Page, while PES has for Morrowind (you know that don't you). :wink_smile: