Very interesting lineup. The Goethe institute seems to be improving a bit with the selection of german films they are showing. 

My recommendations:
Lucy
Nothing Ventured
Rhythm is it!
Summer in Berlin
Windows on Monday

If you watch only these five films, you will get a good idea of the quality and the different approaches of current german cinema.

And you probably also can't go wrong with these three:
The Free Will
Frozen Angels
Into great Silence

And if they haven't passed away
Can't tell you much on that one. I think it's the last part of a long documentary series on german people from a particular town that strated some 30 years ago, and had more than ten entries. Haven't seen any of them, because I wasn't (and am still not) interested. Would be interesting to read a foreigner's review though. 

Barefoot
Entertaining romantic comedy about a guy without orientation in his life who falls in love with a mental patient. Mediocre, but I found it charming. If you want to be entertained.

Crossing the Bridge
Documentary on music scene in Turkey by Fatih Akin ("Head-on"). Heard and read very good things about it. It is said to take a similar approach like Wenders Buena Vista Social Club (1999). Should be interesting if you're into music.

Elementary Particles
New film by eccentric filmmaker Oskar Roehler, it is said to be his most mainstream, though that probably doesn't mean much in his case. Critics were mixed, I can't say anything about it. Should have good performances though. Ah, it's an adaptation of the Houllebeq novel, but with a different aproach/moral.

The Free Will
Sadly I also haven't seen this one myself. But I recommend it for you to watch, anyway. Features two of the best younger german actors, Sabine Timoteo and Jrgen Vogel. Vogel plays a rapist who is released after several years from a mental hospital and tries to find a way back to normal life. But it doesn't work. It is said to be very dark and bleak.
I would like to read a review on it by you, hengcs. 

Frozen Angels
Have this on Video, but not watched yet. About scientific ways of conceiving children, this should be very interesting! You probably should consider watching it.

Happy as One
Watched this on the Berlin Film Festival. Independent film about people trying to connect with each other. I didn't like it, but it might be interesting for others. 

Into Great Silence
Haven't seen, but a review of another film by Groning is here, where arsaib also posted some info on this one. Recommended

Lucy
17 year old Mother struggles with her child and her life. Recommended. My comments can be found here (you have to scroll down to the short comments).

Nothing Ventured
One of the more recent films by great german Filmmaker Harun Farocki. Two parties trying to make a deal with each other, this is a documentary a la Hitchcock. Says much about the workings of our money oriented society. Watch this!

Red Cockatoo, The
New film by Dominik Graf, one of the better german directors, about german youth before the completion of the Berlin Wall in 1961. Should be very interesting. Review of another film by him is here.

Requiem
New film by talented german director Hans Christian-Schmid that won dozens of awards and was praised by the critics over the world. Not recommended by me, though. My review is here.

Rhythm is it!
Documentary about a school, were children are motivated by professional dance teachers to gain the confidence to perform "Le sacre du printemps" on stage. Great inspirational film, was one of the best in 2004, imo. Watch it, I'm sure you'll enjoy it. 
Too bad I haven't written any comments on it.

Summer in Berlin
Very good film by one of the best german filmmakers, Andreas Dresen. Two women in their mid 30s are struggling with everyday life in Berlin. Trying to find a job and a place in life, what both have is ultimately each other. Entertaining and profound. Rated it 70/100. Go see it, I'm sure you'l like it hengcs.

Tough Enough
Controversial german film about a young kid who gets beaten up in school and tries to stand up against a brutal environment. Liked by critics and audiences alike, it is said to take a realist approach to its topic. Probably worth watching.

Windows on Monday
Very honest and difficult film about relationships in germany with people in their 20s/30s. Has some humor, but you definitely won't be entertained in the usual sense. Pretty bleak, but that's what I probably consider the hope and future of german cinema. Recommended. You can read my thoughts here (scroll down to the short comments).