• no more security updates

That may cause a problem, but XP is so old, perhaps hackers will loose interest.

• no more driver updates = no support for recent / new hardware

No problem, old machines, so they will not be updated with that stuff.

• no support for recent / new software (Office 2015, Poser 2015, Vue 2015, ...)

I'm sure that on those Poser 8, OpenOffice and so on will run fine for years. I'm not in the habit of updating everything just because there's a new version. If it doesn't offer anthing I need, then I'll don't update at all.

• no more respons from the MS Helpdesk

I never called them :-)

• and eventually: no more MS webpages to download Service Packs, Knowledge Base patches, etc

In case of crash that may be a problem indeed, but it may still take a while until everything is gone.

In case they crash and can't be recovered, it's time to upgrade or move to new machines.

Artwork and 3DToons items, create the perfect place for you toon and other figures!

http://www.renderosity.com/mod/bcs/index.php?vendor=23722

Due to the childish TOS changes, I'm not allowed to link to my other products outside of Rendo anymore :(

Food for thought.....
https://www.youtube.com/watch?v=pYZw0dfLmLk