I use Breezy with quite a bit of non-standard stuff installed, and I have not had a problem yet. I installed it on an IBM t42p laptop.
I play various media files (from music to divx), watch DVDs, play CDs, do a small amount of photo manipulation via Gimp, surf the web, check email, ssh all over the neighborhood, run desklets, gaim, gkrellm, generate PDFs and a whole bunch of other stuff.
My desktop has only crashed twice, and that's been after I've hacked about a bit and made a mistake. It's been running since August (started out on Warty).
I also run the server edition on a whitebox which has been up and running for several months. It sees fairly high traffic on it's samba shares from all sorts of clients and most of the time I'm not even aware that it exists.
Hope that helps.
Ben