the best order for you is;
oblivion
patch 1.2
KoTN
S.I
this gives the latest version of 1.2 which is compatible with most mods and mod updates.
I believe OOO is trialing a beta patch so you may want to go to the beth forums and check it out under the mods section. i don't use OOO so i don't know how compatible with 1.2 or S.I it is.
also if you want OOO you'll want to start it afresh as its involved to install it and use a save game.
best bet is to NOT load S.I yet.
wait for the next OOO patch update and next official beth update then load S.I otherwise you might end up in trouble.
the unofficial bug fix can be found
HERE
basically if you don't use it your game will be ruined within 50 hrs!
*Edit* patch 1.32 for OOO is now public. theres a big thread on it within the mod section at beth's forums. you might want to read up on S.I compatibility so you can get S.I installed.