It might be interesting for the site to display some basic info about users in the avatar sections by their names. I'm thinking dead simple stuff such as what camera they use and whether they're pro or amateur (i.e. whether they make money from their work or not).
Hmmm. I'm not so sure, and I don't see how it would help the quality of the answers given. Votes give a fair indication of the quality and suitability of an answer, in general, and rep gives an idea of how experienced the user is on photo.SE. Of course, if you want to find out about a user, feel free to browse through to their profile, but I don't think it adds anything to the question/answer page.
We can already write anything we like in our profiles.
Personally I loathe lists of gear as a defining characteristic of a photographer; if we're going to stick something by the avatar it should be links to our work, not to a list of receipts.
I'll note that I say this despite the fact I love keeping that kind of list; I just think it's irrelevant about 99% percent of the time. The other 1% is when people ask "What sort of gear have you collected over the years?"
This kinda falls into the "signatures" category, and the FAQ currently reads:
Please don't use signatures or taglines in your posts. Every post you make is already "signed" with your standard user card, which links directly back to your user page. Your user page belongs to you — fill it with interesting information about your interests, links to cool stuff you've worked on, or whatever else you like!