Good choice for you. I am going to do the reverse. I am alway tagged with my 60D most of the time. Whenever the weather is nice or great situation appeared, I get it out but I feel like not spontaneous as approach. I think the G1X will give me this capability to stop my bicycle and shoot rapidly that I am missing. To conclude, I would say that we want what we not have. Maybe I will do the reverse later. And it is not a photography anymore :)
I've gone a similar way. I used to have a dSLR and a compact, and always found the compact lacking a bit for stock use. I ended up splitting the difference and moving to the micro four thirds format. With the OM-D and a pancake lens it is truly similar in size to the Canon G1X, but even with 4 or 5 primes it still fits into a small bag... Love having my 'best' camera with me at all times.
I do the extension tube thing too - makes for a handy macro lens in a pinch. Here is a shot with my 14mm pancake lens and 10mm extension tube combo while out skiing:
Here is a look at how truly small the Olympus OM-D is :) Mind you, the sensor is smaller than the one in the G1-X by a little bit: Size comparison
40mm handhold at 1/40 f4 ISO800 with CANON 5DII --- took this shot while strolling through the city - I suddenly can do handhold up to 1/25 with avoiding shaken pics - with the 50mm I couldn't - there it was usually 1/60 -- this was also one of the typical situations where I usually used the G1X -
Nikon D700 with Nikkor's, Nikon 90x, Leica X2, Canon S100
Very interesting post coz I am in the same dilema, would like to have a second camera for travel and "always with me ", my doubt was exactly that: to buy a good compact or a second hand 5d (I owe already a pancake).