Many designers love Swiss Design / the International Style that grew from the Bauhaus. Here's a few of my favorite resources for viewing / buying posters & prints from the era
Have you ever had the urge to own original International Style posters? Here's a collection of many, ranging from the affordable to the thousands of dollars. Also a great resource for finding examples of obscure posters.
The great postfolio of Josef Müller-Brockmann works on Flickr is a fun resource ...if you aren't a fan of Helvetica, go ahead and pass on this one.
Blanka is a great resource for one-off or limited-run posters. You can view low-res or buy to hang at home. Very diverse and usually progressive work. The man behind it also has his personal work at Print-Process Poster Designs.
Punk Rock and Swiss Design are posters created from actual shows / lineups. Interesting place to see many of the common design schemas and a great starting place for design inspiration when making that minimalist book cover or poster design for yourself.