As said, any Avid lever. I have an Sd7, one of the older ones on which the lever blade isn't "hollow" and doesn't bend, and it's awesome.
I have Avid SdTI arms, which are so solid it's just daft! They work so well.
A Clarkes cable(I've never noticed a MAJOR difference in cables), lubed up.
Heatsink CNC backings with Rock Green material on a completely dead grind and it's really impressive.
But like the others said, any avid set p will work well, and is very cheap!