Without a data plan, you don't need to be concerned about 3G.
The 8900 has a better camera (3.2mp vs 2.0 on the Bold)
The 8900 has double the application memory of the Bold.
Without the Data Plan you will will have a nice PIM device and phone for texting, and decent fast WiFi browser. Many apps will not work with out the Data (BIS) plan, such as Facebook (you can use the mobile site though) and some twitter apps.