If you can view this page on something awful, this has really clear instructions on getting it all modded up:

Let's Reinstall Oblivion v.3

Also, another alternative is to try that total conversion I mentioned recently called Nehrim which is a completely new game. So far it's been really fun:

Nehrim

"A massive project put together with a large dose of efficient German engineering, this is a total conversion mod for Oblivion that turns it into the game it should have been. Won't go into any great detail about it since it has it's own official thread, but I will say, on a personal level, that even a heavily modded version of Oblivion can't compare with this." - ebert