Leroux: Even though I don't like it, I understand the reasons for not offering demos. But just to act as a counterbalance to the members who said they hardly ever buy a game after trying the demo, I'd like to say that during the past years I have bought several great games at full price
only on account of my experience with the demos and I wouldn't have risked spending that money on them otherwise (e.g. Fortune Summoners, Knights of the Chalice, Driftmoon, To the Moon, Defender's Quest etc.).
Well, demos aren't bad from a consumer stand point, just from the developer side.
I understand you're saying that there were times where it motivated a purchase from you, I have good memories from demos too: my aunt had a cd with a compilation of PC demos when I was little that I played to death and am currently looking for the games on it, despite not remembering a single title (found Broken Sword 2 and Hocus Pocus), I also had a cd with demos that came with my PS1 and I played everything in there dozens of times, even that shitty Barbie: Explorer, and I bought most games from there.
Maybe you could blame it on being jaded, but that changed lately. Some years ago when I finally got my PS3 connected to the PSN I played every single demo in there, and the only one I ended up buying was Bioshock, everything else I either didn't like or would have bought anyway. Now I usually have my mind made up long prior to a demo and don't even bother playing them anymore.
Not to say I've completely changed, Strike Suit Zero had a few conflicting reviews when it came out and it could really use a demo. I ended up having to pirate it and after playing through the tutorial I happily bought it.
P.S.: Wow! You've played Fortune Summoners? I haven't gotten around to it yet, but have you tried Recettear? It's from the same publisher and it's demo made me immediately buy it.