About the images, Ferret,
Newnigma, is a good choice but don't like the image organisation, and presentation, PLI images are too new, and not for DM800, i use pli on DM500...
The pli team speciality is DM500 (look at the download stats on their site)
Actually for me, Gemini 5.1 is the better choice, the image organisation is better than Newnigma...
LT6 is very good and you have lot of skins to personalise it, LT 6.5 is nice also, but only few skins... i would go for LT images but i don't like the mini tv in channel list...
With the recent images (year 2010 images) i prefer :
1/ Gemini 5.1 (because of EPG 7 days)
2/ LT 6 / LT6.5
3/ newnigma (i don't like the presentation but it's an good image...)
4/ ooZoon latest is nice also
With old images :
The best for me is Nabilosat Blackhole 12, because in 2009, it was the only one image wich work with Csat FR epg...
I'm actually using Gemini 5.1, and i'ts ok, but if i have found pleasant skin for LT image, i would go for LT6 or LT6.5...
Hope it will help...
ps : be aware if your box is an clone, choose an image wich will be compatible with your bootloader...