Impress

Inkscape vector graphics (.svg) appear a little bit blurry when used in libre office impress (Version: LibreOffice 3.5.7.2, Build ID: 350m1(Build:2)), especially when text is visible on the graphics. 

I think the easiest workaround is to export the inkscape graphic as a .png bitmap

File -> Export Bitmap

I got good results with the default settings (90 dpi).

The generated png can then be included into Impress.

There's a cool add-on (ExpandAnimations) for Libre Office Impress out there that let's you export a Libre Office presentation, even with animated (appear, disapper) effects.

You can download it at

https://raw.github.com/monperrus/ExpandAnimations/master/dist/ExpandAnimations-0.4.oxt

Open it with Libre Office.

Once the add-on is installed you can export animated presentations to pdf via