I never thought staying in a prison would be so nice, although I have heard they can also be quite nice here in England, if you stay in an open one....
Personally, I thought Ljubljana (try saying that sober is hard enough, never mind after a few "pivo") was a bit boring, but then I'd just come from Budapest and was living near to Prague at the time. It's really small, (the "international" bus station opposite the train station has to be seen to be believed...the footy song (in UK, this will be completely lost on non Brits!) " my garden shed is bigger than this" actually runs true!) so it felt more like a big student town rather than a capital city.
If you have the chance, (and seriously 2 days would be enough) head off to Lake Bled and the Krajnska Gorge This has to be one of the most stunning places I've seen anywhere in Europe, and that's comparing places like the Alps etc etc. It takes about 3 hours from Ljubljana and it's well worth the trip. Also, there are some amazing caves and near to this (Pojstona as per post above) the famous white horses (something like lupica) which I would both recommend strongly. As per earlier post, both are right by the border to Trieste so why not try and break up your journey to L in the first instance? Enjoy.
ps Croatia is even better!
[ Edit: Edited on Mar 19, 2007, at 11:42 AM by PeteW27 ]