Is it worth to install a gas stove with a big gas bottle in the kitchen?
Yes. 

It's much more fun to cook with gas, and the way I see it, any incentive I can provide for myself to cook good food at home is a major net positive in quality of life.

The setup I have is three gas burners and one electric stove top element, and an electric oven. The electric stove top really comes in handy when reducing stocks or making long-cooking soups and stews, and it can significantly reduce the amount of gas you use in cooking.

For oven I would definitely go electric. See the When baking is it better to use a gas or electric oven question.

I have one 5 kg liquid gas bottle stashed under the sink, and it lasts 3-4 months of heavy daily cooking for two, maybe 6 months in the summer when I eat more salads etc. In addition I have another 2kg bottle for backup if I run out of gas in the middle of cooking, and for the day or so it takes me to haul another bottle from the store. Having a smaller backup bottle doesn't waste too much space.

I've been considering upgrading to a 11kg composite bottle, which I expect to last 10 months to a year, and it's way more economical. So far though the convenience of having a smaller bottle I can carry to the store for changing without a sweat has been great.