I was wondering if it is worth it upgrading my late 2006 Macbook to Lion or simply leave it on Snow Leopard. It has 1.83ghz processor and 4gb ram (reads 3).
Then general consensus is that Snow Leopard is faster than Lion at most tasks on a Macbook of your vintage. Of course, Lion does have newer features like iCloud as well as still getting security updates for a short while.
I run Lion on a Late 2006 20" iMac, but it has considerably more power than your MacBook graphics wise. I would say stick with Snow Leopard if you want speed and for your mac to not be all that stressed, or go with Lion if you want the updates to the OS, and still supported software. Anyhow for a mac of that caliber I would go with Snow Leopard. Have fun with it!