Jim,
Looking at your position on the bike it seemed to me that it is a little small for you, isn't it?
When I bought my Trek Smover (on my netsite, the one with the Cyber Nexus automatic groupset), I spoke to quite a few dealers in the Benelux, trying to find one who would ship it to me. There were two sizes 55 and 61cm, effective. Normally I take a 58cm bike. The consensus of opinion was to choose the smaller one, 'for the control'. I did, and after a bit of trouble getting the handlebars up above the seat, because I like to sit upright, it fitted me very comfortably. This is an extremely nippy bike, in and out of the traffic like quicksilver but you need to pay attention on the fast curvy downhills if the road is rough. When I got a Utopia Kranich, the idea was different. Their official line is that you buy the size frame which give you the pedal-seat distance with the minimum seat tub extension, and then adjust the length and angle of the stem to bring the handlebars into the right position. It works brilliantly, but its definitely a different paradigm, resulting in a bigger 59cm bike under me. My local bike mechanic, a very old chappie, took one look at it and said, 'That's how a bike should be sized.' It's anyway a different sort of bike to the Trek, with a huge wheelbase, but it feels noticeably more stable, though the turn-in is slower and on the same fast curvy downhills at the more sporting Trek's speeds it takes up more of the road because it wants to understeer, so that you have to pay attention for a different reason, that you don't drift over into the next lane. Oddly enough, on the flat and straight and sweeping bends of main roads the Utopia with its fat tyres is faster and much more fun than the Trek which under those 'ideal' circumstances draws attention to itself by demanding constant small corrections. I do have another bike which at a first glance is nearer the Trek, a Gazelle Toulouse in 58cm, but it's geometry is much more relaxed than the Trek's, and it has the same restful behaviour on the road as the Utopia despite having the same sort of tyres in the same size (Marathon Plus).
If you have a choice between two sizes in the Thorn range, Cedric, you should consider your roads and your riding style before you make the choice. Also which tyres you will use most of the time. If it were me, if I was going to use the bike for relaxed day rides, I'd definitely choose fat tyres, maybe even balloons, and the longer wheelbase. Even fast touring on narrower tyres would be more restful on the longer wheelbase. But if I were talking fast exercise rides on hilly lanes like mine, with either tyre I'd take the shorter wheelbase for the super-responsive handling. (That's different from the Kranich I now use for exercise rides, but the Kranich was intended as an all-round utility bike and just grew to be an all-round favourite for its comfort, whereas now we're talking about a fun bike for a presumably younger, faster man.) Others may have different opinions.
On the roads Jim K are showing -- gee, he wasn't joking about it being hilly! -- that bike under him looks like the sporting choice, though I'd personally move the bars up, and move the grips back by fitting North Road bars, to give a more upright posture for better visibility and steering control. Meeting a big car or a truck at speed on such narrow road can be fraught.
Like Julian says, that action shot is very cool indeed.
Andre Jute
Visit Jute on Bicycles at
http://www.audio-talk.co.uk/fiultra/BICYCLE%20%26%20CYCLING.html 
