I am building a do-all Redline, and I was pondering what cranks and cassette. It seems to me that Using a 53/39 double up front would be great for commuting and recreational racing, and that a large cassette, like an 11-34 9 speed, would have enough low end to offset the high tooth count of the chainrings in trail climbing situations.
I'm not sure off the top of my head what the large chainring's tooth count is on my current mountain bike commuter, but I am pretty sure that it is 46 or 48, and I know I am running a 11-32 in the back, and I find myself spinning my wheels most of the time, and even when stopping at light/stopsigns, I'm not usually dropping more than 3 or 4 gears in the back to start up again.
Does this sound reasonable? Regular road cranks seem to be alot easier to come up on, and cheaper than compact cranksets.
With a cassette of that size you will need a MTB RD (like an XT) to accomodate the large range. Sounds like you want an all purpose bike. Should work. If you don't have STI levers I will be putting a couple of them on eBay this afternoon. Came off a Cross bike.
For your all-around bike my vote goes for a road triple- 52-42-30 or something like that. I have an 11-30 cassette in back. In my opinion the compact double is still too restrictive in gearing for all around use. The weight and lack of close gear ratios are only important if you're road racing. Triple chainrings are not a sign of weakness; they kick ass.
The real answer depends on your cycling strength, but I'll put in a plug for the triple. I switched to a compact ring and found that any time I had to shift in front I had to double or triple shift the rear. I also found that with a big jump in the chain rings and large spacing in the back that I would have to switch chain rings often right around my sweet-spot (16-17 mph on a road bike) to maintain a good cadence. I went back to a triple with closely spaced cassette and find I'm much more comfortable and do much less shifting.