In my opinion it really depends on the scope of your project, the target audience, etc.
You should offer as many options as possible, especially ones that fit your actual community/customers:
- Email is something I'd consider a must-have. Give fans some form of contact if everything else fails. Noone expects instant answers, but it's still something that clearly shows "I don't want to ignore you".
- Forums are a great way to outsource part of customer support to the community itself. Just keep in mind that players or users can't solve everything on their own and you have to keep an eye on them and help where help is needed.
- Ticket systems should be considered mandatory if you've got things people can't discuss in public, like payment issues, account problems, etc. These can be handled through email as well, but ticket systems usually offer a far more organized structure making the whole thing a lot easier for both sides.
- Idea collection can be another thing, especially if you want to work with your community (e.g. determine what they really want next). You can use a forum section for this, but there are also dedicated solutions out there, e.g. getsatisfaction.com, where users can suggest things, they can vote on them, etc.
As for the actual scope, how much you do it yourself, whether you should hire other people to do it,... This really depends on your actual project. In my opinion you could simplify this question to one single formula: The more money you make, the more professional and faster your customer support should solve issues.
For example, if I notice a bug in some open source game, then I don't expect any immediate answer or "thank you". If it takes one or two weeks, it doesn't matter. However, if I can't log in to that MMORPG I'm paying monthly to actually be able to play it, I expect answers within 24 hours, maybe even the same day depending on the actual issue or severity.
If you're making enough money to pay one or two people to actually look after your customers (e.g. answering support enquiries or moderating forums), do so, if you think your overall image (and the community of course) profit from that. But don't forget that for some things like forum moderation you can as well include the community once again. Many dedicated fans will be more than happy to help you building a better community.