[aiharkness]

Here's the deal:

1 - You're friend is sort of correct. The fact is that you will not be able to use ANY BlackBerry branded apps, nor any other apps that require access to the BlackBerry/RIM infrastructure, without a BlackBerry data plan. This will be the case even for wifi. So that includes not just BBM and push email, but the BlackBerry twitter, facebook, etc. and even some third-party apps.

2 - Some carrier's require the BlackBerry data plan in order for wifi to be usable. Do a search on this and see the discussions. Some others, for example T-Mobile USA, do not require it. I don't know about your carrier. See what others say.