A summary of the rules so far:
Rule 1. Gym music must be loud enough to drown the music piped into the gym.
Rule 2. Gym music mustn't make me want to engage too much, singing along or anything else is not advised.
Rule 3. Gym music must motivate me to run.
Rule 4. Gym music needs to keep me interested for at least 45 mins.
Rule 5. Gym music must be interesting enough to stop me watching: The Price is Right with Joe Pescuali (Fortunately there is no sound so I don't have to listen); The New Paul O'Grady Show (He is from Birkenhead); I'm A Celebrity I'm So Desperate To Be Here Show.
Excellent in every way. Good loud tracks (when I worked out how to turn off the setting to protect my eardrums on my iPod). Picked me up at the half hour mark whe I started to flag. Change in styles all the way through kept me interested right to the end. And kept me smiling when I was running.
OK computer (Radiohead)
Not bad. As each track started to play it kept me interested in what was going on but eventually I forgot I was listening as each track was a bit monotonous and a bit the same. Also a bit sad, reminded me a bit of being a teenager, I think.
Blue Light Red Light (Harry Connick Jnr)
I like this album anyway and have had it for a while. Obviously the first track woke me up. But I think I am too familiar with this music to keep me interested for the duration. But I haven't heard the last tracks for a while and I had forgotten that they where really sad so probably not good for the gym.
Next Faures Requiem and any other suggestions (Might try Dans suggestions, nothing in 3/4, thanks John)