My Hacker Newsletter (http://www.hackernewsletter.com) has been killing those averages with about a 55% open rate and 35% click rate, so it really depends on your audience I think.

Last campaign I sent for a client had 60% open and 32% click rate. I've also seen much worse than those stats.

It really depends what you are doing. On a strongly qualified list with content relevant to the users you should be able to do quite well.