For me?
Stage 1: just implementing the possibility to donate. That's a start. Whatever excess money you guys have, can be put towards a raffle every quarter/month/year whatever. People will gladly donate, especially if it's available. My other forum has an announcement every 6 months to remind members to donate. You don't have to, but it makes it easier on Hugh (the owner).
Stage 2: Supporting members benefits. For those that did donate.. special characters/fonts for their names color changes.. whatever. the generic stuff, and a PM box bump in size (nothing major, but probably about twice what it is now.. because lets face it.. it's pitifully small).
Stage 3: Subscribed members if at all possible. For those that agree to pay a monthly subscription fee (like $3 or 5.. whatever) even higher increased PM box sizes.. special titles they can write (like the forum that shall not be named), badges.. whatever. Maybe even a forum for paid members (never was a huge fan of those since the rules were the same in those than as it were on the outside.. however if you made the exception for major rules in there... could be nice).
That's what I'd like to see.. of course this isn't what I'm demanding or what other people want.. this is just me.
The only thing I'm demanding is the possibility to donate.. and an increased PM box size.