I would say that providing admins with the ability to make adjustments to nearly all the YM hardcoded fields would be ideal. Many organizations have small quirks and items that they want to customize. However if that is not possible a few key ones for me include:
-Organization
-Title
-Address Cont.
-Postal Code
-LOCATION - This one drives me a bit nuts.. Opposite of Mr. Duncanson, we need this to clearly say "State" it causes *rampant* confusion among our members and it's appears everywhereeeee.
Thanks for checking into this one!
I'll also throw in a last two cents that it would be ideal if we could have our custom fields appear in the listing wherever we see fit rather than having to have them after the hard coded fields. That way if you have an admin that creates a custom field work around they can put in the right place. We did that for "title" because we needed specific options, wording and drop-downs for that which the hard coded option could not provide. It would prefer it go after or before "name" but instead have it put it somewhere in the middle of personal information, it's a little awkward.