your right chris, cool art should be on the walls and ceiling but there are often times where walls are just plastered with random crap like outdated flyers and posters, torn pictures etc...not art. It's really a case of, if there's too much stuff on the walls, even if its all cool art, then it starts looking messy.
The pictures of the room you posted do look good, it's tidyer and a lot more welcoming. i think one of the main problems with the room is not what it looks like at night, because some nice candles and a good bunch of people can always make a place look inviting, but more of how it looks during the day when there are less people in there and no warm, bright candles or atmosphere inviting people in. I definately don't want the room to look all clinical and boring as thats not what the place is like but just have to be careful about how much random crap is in there. During the day the room doesn't get loads of light coming in, there are no additional lights on in there, most people are sat in the warmer main cafe area. All that as well as the dark walls, make it a bit gloomy, which is not great when trying to entice people in. One of the main things is the lack of nice sofas in the front room, surely that instantly makes it look a bit more inviting. that and a few plants, preferably not dying ones and it would start looking nice....nice! sorry i hate that word too but i used the word inviting too much already...how about cosy? especially since we don't seem to have any summer, people want to escape to a cozy cafe out of the rain.
Also, how about a huge menu on one of the walls of the front room?, not only will the prices get people coming in, but others might actually realise that we are also a cafe.
We could also do with some sort of very brief one sentence slog-esque thing in there too or on the window. i know we've got the huge poster telling people what to do, but something that sums the Forest up in 1 sentence would be great. e.g. "Cafe and arts venue, free live music/film/spoken word events, art exhibitions, great vegetarian food and drink. Everyday 10am till 11pm". I know that could be better but i think you get my drift. it instantly tells people what we are, who we are, what we do and when we do it...sort of. What do you think? I'm just trying to view the place as if I'd never ever been there before and what would entice me in.