Can see why you might want to try Big Apples - I guess a _bit_ of suspension might occasionally be quite nice. But I'd be a bit worried re the built in mudguards and the caliper brakes, both of which might be a bit of a tight fit for Big Apples (not that I've tried). But as the bike is stiff and strong as anything, its no real big deal to take bumps by standing on the pedals.
On gears, I think it _might_ be worth sometime getting the rear wheel rebuilt to take a capreo cassette. But until I run out of better things to spend £150 on (new hub, new cassette, wheel build), I probably won't bother. And its not as if the bike is going to be taken to the races, most of the time I'm in middle-ish gears between lights, and if I really want to put some extra speed on, I just have to pedal a bit faster....