Apple just released the iPhone 2.2.1  firmware update.  This is a minor update:

• Improve general stability of the Safari
• Fix issue  where some images saved from mail do not display correctly in the Camera Roll.

Sometimes firmware updates can bring unexpected problems.  For instance, many people experienced significant reduction in battery life when updated to iPhone 2.2.  Therefore, unless these two issues caused a lot of problems for you before, I would not recommend to update to 2.2.1.

Related posts:

1. Firmware 2.2.1 upgrade crashed iTunes
2. iPhone 2.2 firmware hidden security features
3. iPhone 2.1 firmware