This can create endless discussion, but there is one tenet I would hold to whenever deciding what license to use: DON'T CREATE A NEW ONE!!
No matter how persuasive your legal guy's arguments that, because no current license exactly meets your project's unique needs, you should write your own, or even just "slightly modify" an existing one, treat him like a programmer coming to you arguing that he just HAS to use a GOTO statement because nothing else in the language will work.
Other advice:
Choose one which has major usage (see http://freshmeat.net/stats/#license)
See David A. Wheeler's discussion of why to choose a license compatible with the GPL - http://www.dwheeler.com/essays/gpl-compatible.html.
