Should I take the effort to pursue badges or just focus on good questions and answers? This is a never-ending-task. Is this useful or should I spend my energy in something else?
You obtain badges by focusing on good questions and answers.
The SE sites work because they have good, well answered questions. The badges help focus the mind. They let you know what can be achieved.
Apart from stating the obvious - the Good Answer badge and the like, there are badges that guide you in supporting the site generally. Voting shows your approval of the good questions and answers of others - you can't expect to receive votes if you don't give them. That is what Electorate is for.
Also, badges for helping to improve the Q&As of others - Copy Editor.
Don't become obsessed with badges, they are a bit of fun on the side that can help to keep up your interest. Just remember badges and good posts are not mutually exclusive - they are intertwined.
It's really up to you.
Badges are meant to encourage behaviour that improves the site.
If you start voting recklessly just to get a badge, that's bad.
If you vote to get the badge, but make a point of upvoting the good and downvoting the bad, that's perfect.
And yes, there are a lot of badges nowadays. It's not even possible to get them all - "Beta" being the prime example. That was for people who participated in a private beta.
Focus on the tasks you like. And if a there is a specific badge to be earned by that task, by all means try to get it - or ignore it. As long as you keep in mind that the ultimate purpose of reputation points and badges is to uphold the quality of the site.
Note that, if you intend to focus on a specific badge, you can set the badge tracker to display that one, instead of the automatically selected one.