The specs to your MacBook are [http://www.everymac.com/systems/apple/macbook/stats/macbook_2.0_black.html|here.] With the bottom case and the backlight inverter cable you have the best you can go up to is the 2.16 GHz Core 2 Duo. That doesn't buy you much by looking at the numbers. However that processor/board has twice the processor cache 2 MB vs 4 MB which means it can store more repeated subroutines from programs, making it faster on many operations. That board also supports more RAM, memory, than your current board. The 2.16 is also 64 bit architecture and yours is 32 bit. There are enough subtle differences that you would realize better performance. The specs for the 2.16 are [http://www.everymac.com/systems/apple/macbook/stats/macbook-core-2-duo-2.16-black-13-mid-2007-specs.html|here.]
Another option you have is to buy the bottom case from the 2008 black MacBook, along with the heatsink and inverter cable to fit that era of MacBook and you can go up to the 2.4 GHz board.
[http://www.youtube.com/watch?v=eoP2h27UYzc|Here is a video] explaining the things you need to pay attention to when changing motherboards for the A1181, pre Unibody, MacBooks.
I hope I have helped you more than confused you.