I've just bought my fourth BMW (a manual Z4 Coupe). I only got a manual because the (otherwise) right car came along at the right price. My last car was a 325 Coupe (Auto) and I have driven an auto Z4 Coupe.
My view is that auto (as in Steptronic or the Porsche version Tiptronic) is so good now that there is very little reason to want anything else on a road car. I drive very fast as a habit but I still have to contend with everyday traffic. Auto makes stop/start & slow moving traffic painless whereas a manual car is a pain in these conditions.
With the auto box you tend to leave them in auto (or perhaps Sport if you are in a hurry). The reason for the paddles (which I agree are a bit of a gimmick) or a dab on the lever is normally to change down eg so that you can take a roundabout in 2nd or 3rd and be ready to powerout. It's also handy in town (stick it in third and you'll tend to do 30, in Drive the speed will tend to creep up to 40/50 - Really!) On a couple of occasions when I had the misfortune to have to drive the 325 in the snow it also helps to be able to pull away in a higher gear. I guess there may be odd occasions where if you are a very good driver, very familiar with your car and driving in the sort of way that would be very hard to defend on the road you might be accelerating in a long bend and want to change up before it to avoid a change mid bend but I can't think that I've ever needed it (gearchanges are so smooth any way that you would need to be absolutely on the limit for it to be a big problem).
Incidentally my 325 would change up at the indicated redline automatically. THere would be no drop in power before the change - this makes it very easy to drive flat out and in practice puts you at an advantage over drivers of manual cars that are trying to keep up (on the road).
I imagine that manual cars have the redline set higher so if your not slick with the timing of your gear changes your likely to go past peak power and lose your rate of acceleration before changing up every now and then.
I know that people feel very passionately about manual cars but speaking as someone that has owned a lot of cars, knows a lot about how they work and drives a lot (and fast) I fail to see why you would ever want anything other than a modern auto (unless you drive on the track a lot - but frankly even then.....)
