The reason I've taken to using my big chain on flattish ground is that my chain doesn't make noise there and behaves itself. My rear cassette is 11-34, and some of the jumps between gears are pretty large.

In some cases I have a smaller range if I jump between the chains for some of the gear progression - someone checked out the gear ratio for my bike on Sheldon's site and suggested it. I've also found that I go a couple of mph faster if I am in the big chain on flattish ground (with the middle gear on the rear). My max speed so far that isn't downhill is 19.9 mph.

Oakleaf - it rubs on the same part of the FD cage regardless of what gear I am in.

As far as cadence is concerned, I try my best to keep it between 80-95 and as generally close to 85-89 as I can. Going uphill can generally keep it in the 70's - though when I am really struggling to get up that hill I don't think to look at my cadence but am focusing purely on perceived effort. On sprint intervals I am paying attention to my HRM (it is mounted on my bike) but can get cadence to 105 and this is typically on the big chain.

I understand about trying not to shift under load, so I try to anticipate when I will need to shift and to do it a little early, but not so early that I lose all of my speed too early. I am not successful with this much of the time but I seem to be improving.

I do try to "soft pedal" when I shift, and sometimes will even coast for the briefest of seconds while I shift and then start pedaling to complete the shift. This is a carry-over from when I first started to learn how to shift and at that time my coordination was worse and would go all over the road if I tried to shift and pedal at the same time I will pay attention to this in case I am not soft-pedaling as much as I think I am...

Thanks everyone, you have given me some things to think about and check out. Cleaning my drive train does seem a good idea, but there does seem to be more going on than that. At least my LBS will appreciate a clean bike later this week!